Periventricular leucomalacia (PVL)-like lesions in two neonatal cynomolgus monkeys (Macaca fascicularis)

Periventricular leucomalacia (PVL) is a lesion of immature cerebral white matter that occurs in the perinatal period. In man, PVL is the predominant form of brain injury and a cause of cerebral palsy and cognitive deficits in premature infants. PVL affects fetuses and newborns, particularly those who have undergone oxygen deprivation as may occur in premature birth. Many clinical and pathological studies of PVL have been performed in man, but there is no clear definition of PVL in animals. A few spontaneous PVL-like cases in puppies or experimental cases in other animal species have been reported. The present study reports the histopathological and immunohistochemical features of PVL-like lesions in two neonatal cynomolgus monkeys. In both cases, there was cerebral white matter necrosis with marked infiltration of lipid-laden phagocytes and a reduction of neurons in the cerebral cortex. In case 1 there was extensive cavitation of the cerebral white matter. In case 2 there was reactive astrocytosis associated with a decrease in oligodendroglial cells and a decrease in cerebral white matter myelin. To our knowledge, this is the first report of PVL-like leucoencephalomalacia in non-human primates.

Collagen-coated poly(L-lactide-co-ɛ-caprolactone) film: a promising scaffold for cultured periosteal sheets

BACKGROUND

We previously demonstrated that human periosteal sheets prepared on culture dishes function as an osteogenic "graft material" applicable to periodontal regenerative therapy. However, a lower level of initial adhesion of the excised periosteum tissue segments to culture dishes was a critical point that compromised the successful preparation of functional periosteal sheets. To improve on this weakness, we developed a transparent, biodegradable poly(L-lactide-co-ɛ-caprolactone) (LCL) film and tested its function as a scaffold and carrier of periosteal sheets.

METHODS

Human periosteum tissue segments excised from alveolar bone of healthy donors were cultured on type I atelocollagen-coated LCL films. Initial adhesion was examined by simple agitation. Cell outgrowth and in vitro mineralization were cytohistochemically examined. Osteogenic activity was histochemically examined in an animal implantation model using nude mice.

RESULTS

Surface collagen-coating modified the hydrophobic nature of LCL and substantially improved the initial adhesion. Compared to cultures in plastic dishes, the growth rate was delayed in non-coated films, but not in collagen-coated films. In the trimming process for animal implantation, periosteal sheets were frequently detached from non-coated films, but not from collagen-coated films. Regardless of collagen-coating, LCL films did not cause any significant infiltration of inflammatory cells, or negatively impact mineralized tissue formation.

CONCLUSIONS

Collagen-coating improved the initial adhesion of periosteum segments, which facilitated cell outgrowth and also handling efficiency on implantation. Therefore, we believe that once evaluated in human studies, our collagen-coated LCL film will contribute to improving the periodontal regenerative methodology with the application of cultured autologous periosteal sheets.

Calcitonin receptor binding in the hen neurohypophysis before and after oviposition

To demonstrate the presence of a receptor for calcitonin (CT) in the hen neurohypophysis and to estimate the time of action of CT on the neurohypophysis during the oviposition cycle in relation to arginine vasotocin (AVT) release, binding of (125)I-labeled chicken CT in plasma membrane fractions of the hen neurohypophysis was measured by the use of a radioligand binding assay. The binding specificity, reversibility, high affinity, and limited capacity are characteristics of a CT receptor. Therefore, it was elucidated that the CT receptor might exist in the plasma membrane of the neurohypophysis of hens. The binding affinity of CT receptor increased at 30 min before oviposition and the binding capacity was decreased at 15 min before oviposition. However, no change was found in non-laying hens during a 24-h period. Such changes in the CT receptor binding were found at 10 min after an i.v. injection of chicken CT into non-laying hens with an increase in the blood level of AVT. The changes in the binding affinity and capacity of CT receptor of the neurohypophysis may be related to AVT release partly at oviposition time in the hen.

Large-Eddy Simulation on turbulent flow and plume dispersion over a 2-dimensional hill

Abstract. The dispersion analysis of airborne contaminants including radioactive substances from industrial or nuclear facilities is an important issue for air quality maintenance and safety assessment. In Japan, many nuclear power plants are located at complex coastal terrains. In these cases, terrain effects on the turbulent flow and plume dispersion should be investigated. In this study, we perform Large-Eddy Simulation (LES) of turbulent flow and plume dispersion over a 2-dimensional hill flow and investigate the characteristics of mean and fluctuating concentrations.

Olmesartan inhibits angiotensin II-Induced migration of vascular smooth muscle cells through Src and mitogen-activated protein kinase pathways

Clinical studies have shown that angiotensin-receptor blockers (ARBs) reduce the risk of cardiovascular diseases in hypertensive patients. It is assumed that the reduction of the risk by ARBs may be attributed in part to the inhibition of angiotensin II (AII)-induced vascular smooth muscle cell (VSMC) migration associated with atherosclerosis. However, the effect of ARBs on AII-induced changes in intracellular signaling and resultant cell migration has not been well established. Here, we investigated the effect of olmesartan, an ARB, on AII-induced extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK) activation and rat aortic smooth muscle cell (RASMC) migration. Olmesartan inhibited AII-induced ERK1/2 and JNK activation at lower concentrations (10 nM). On the other hand, PP2, a Src tyrosine kinase inhibitor, also inhibited AII-induced ERK1/2 and JNK activation, but its effect on ERK1/2 was less pronounced than that of olmesartan. Olmesartan, U0126 (an ERK1/2 inhibitor), SP600125 (a JNK inhibitor), and PP2 potently inhibited AII-induced RASMC migration. From these findings, it was inferred that angiotensin-receptor blockade by olmesartan results in the inhibition of AII-induced activation of Src, ERK1/2, and JNK in RASMC. Olmesartan may be a potent inhibitor of AII-induced VSMC migration, which may be involved in the progression of atherosclerosis.

Human periosteum-derived cells combined with superporous hydroxyapatite blocks used as an osteogenic bone substitute for periodontal regenerative therapy: an animal implantation study using nude mice

BACKGROUND

A superporous (85%) hydroxyapatite (HA) block was recently developed to improve osteoconductivity, but it was often not clinically successful when used to treat periodontal osseous defects. The primary purpose of this study is to develop a clinically applicable tissue-engineered bone substitute using this HA block and human alveolar periosteum-derived cells.

METHODS

Commercially available superporous HA blocks were acid treated and subjected to a three-dimensional (3D) culture for periosteal cell cultivation. Cells in the pore regions of the treated HA block were observed on the fracture surface by scanning electron microscopy. After osteogenic induction, the cell-HA complexes were implanted subcutaneously in nude mice. Osteoid formation was histologically evaluated.

RESULTS

Acid treatment enlarged the interconnections among pores, resulting in the deep penetration of periosteal cells. Under these conditions, cells were maintained for >2 weeks without appreciable cell death in the deep pore regions of the HA block. The cell-HA complexes that received in vitro osteogenic induction formed osteoids in pore regions of the treated HA blocks in vivo. In contrast, most pore regions in the non-pretreated, cell-free HA blocks that were evaluated in vivo remained cell free.

CONCLUSIONS

Our findings suggest that an acid-treated HA block could function as a better scaffold for the 3D high-density culture of human periosteal cells in vitro, and this cell-HA complex had significant osteogenic potential at the site of implantation in vivo. Compared with the cell-free HA block, our cell-HA complex using periosteal cells, which are the most accessible for clinical periodontists, showed promising results as a bone substitute in periodontal regenerative therapy.

Etoposide induces G2/M arrest and apoptosis in neural progenitor cells via DNA damage and an ATM/p53-related pathway

Etoposide (VP-16), an anti-tumor agent, is a topoisomerase II inhibitor that causes DNA damage. In our previous studies, it was shown that VP-16 induces S-phase accumulation and G2/M arrest, eventually resulting in apoptosis, through p53-related pathway in the mouse fetal brain. We injected 4 mg/kg of VP-16 into pregnant mice on day 12 of gestation, and the fetuses were investigated for the cell cycle checkpoint and mechanism of apoptosis. The transition of the neural progenitor cells in the fetuses was delayed as compared to that in the control, and most of the apoptotic cells were BrdU positive. VP-16-induced S-phase accumulation was brought about by the acceleration of G1/S transition rather than by the inhibition of S-phase progression. Phosphorylation of ataxia telangiectasia-mutated kinase (ATM) at Ser1981 and gammaH2AX after VP-16 treatment showed DNA damage. p53 was phosphorylated at Ser15 and 20 and increased after activation of the ATM kinase pathway. Cdc25A degradation might induce the inhibition of S-phase progression. It is supposed that an increase in cyclin A might accelerate G1/S progression. It is also indicated that VP-16-induced G2/M arrest is caused by p21, which inactivates cyclin B-Cdc2 complex and eventually prevents mitotic entry. In p53-deficient fetal brains, G2/M and apoptosis were almost abrogated, although S-phase accumulation still occurred. It is suggested that VP-16 induced p53-independent S-phase accumulation, and p53-dependent G2/M arrest and apoptosis of the neural progenitor cells in fetal mouse brain.

Immunohistochemical Characterization of Canine Neuroepithelial Tumors

The expression of cell differentiation and proliferation markers of canine neuroepithelial tumors was examined immunohistochemically to identify the histogenesis of these tumors. Astrocytomas ( n = 4) consisted of cells positive for glial fibrillary acidic protein (GFAP) and nestin and a few cells positive for doublecortin (DCX). Immunoreactive cells for receptor tyrosine kinases (epidermal growth factor receptor and c-erbB2) and their downstream molecules (phospho-extracellular signal-regulated kinase 1/2 and phospho-Akt) were often detected in astrocytomas, especially in medium- and high-grade tumors. Gliomatosis cerebri ( n = 3) consisted of cells positive for ionized calcium–binding adaptor molecule 1 and GFAP, including a minor population of cells positive for nestin, DCX, and beta III tubulin, suggesting their glial differentiation. In choroid plexus tumors ( n = 4), most tumor cells were positive for cytokeratins AE1/AE3 and 18, and few were positive for GFAP. The majority of cells of oligodendrogliomas ( n = 5) were DCX positive, but the tumors also contained minor populations of cells positive for GFAP, nestin, or beta III tubulin. Primitive neuroectodermal tumors (PNETs; n = 2) consisted of heterogeneous cell populations, and the tumor cells were positive for nestin, beta III tubulin, and DCX, suggesting glial and neuronal differentiation. The major population of neuroblastoma cells ( n = 3) were positive for beta III tubulin and DCX, suggesting single neuronal differentiation. As for antiapoptotic cell death molecules, most tumor cells in the choroid plexus tumors, PNETs, and neuroblastomas were intensely positive for Bcl-2 and Bcl-xL, whereas those in gliomatosis cerebri were almost negative. In astrocytomas, Bcl-xL-positive cells predominated over Bcl-2-positive cells, but the opposite was observed in oligodendrogliomas. The immunohistochemical results were analyzed by hierarchical clustering, and the constructed dendrogram clearly indicated a novel position of oligodendrogliomas: the primitive glial and neuronal differentiation.

Osteogenic activity of human periosteal sheets cultured on salmon collagen-coated ePTFE meshes

Our animal implantation studies have demonstrated that, after osteogenic processing, cultured human periosteal sheets form osteoid tissue ectopically without the aid of conventional scaffolding materials. To improve the osteogenic activity of these periosteal sheets, we have tested the effects of including a scaffold made of salmon collagen-coated ePTFE mesh. Periosteal sheets were produced with minimal manipulation without enzymatic digestion. Outgrown cells penetrated into the coated mesh fiber networks to form complex multicellular layers and increased expression of alkaline phosphatase activity in response to the osteoinduction. In vitro mineralization was notably enhanced in the original tissue segment regions, but numerous micro-mineral deposits were also formed on the coated-fiber networks. When implanted subcutaneously into nude mice, periosteal sheets efficiently form osteoid around the mineral deposits. These findings suggest that the intricate three-dimensional mesh composed of collagen-coated fibers substantially augmented the osteogenic activity of human periosteal sheets both in vitro and in vivo.

Three-dimensional structure of the alpha1-beta complex in the skeletal muscle dihydropyridine receptor by single-particle electron microscopy

The dihydropyridine receptor (DHPR) is a protein complex that consists of five distinct subunits of alpha(1), alpha(2), beta, gamma and delta and functions as a voltage-dependent L-type Ca(2+) channel. Here we purified the alpha(1)-beta complex (approximately 250 kDa) from the rabbit skeletal muscle DHPR and reconstructed its three-dimensional (3D) structure to 38 A resolution by single particle analysis of negative staining electron microscopy. The alpha(1)-beta structure exhibited two unique regions: a pseudo-4-fold petaloid region and an elongated region. X-ray crystallographic models of a homologous voltage-dependent K(+) channel and the beta subunit fit well into the individual regions of the alpha(1)-beta structure, revealing that the two regions correspond to the transmembrane alpha(1) and the cytoplasmic beta subunits, respectively. In addition, 3D reconstruction and immuno-electron microscopic analysis performed on the independently purified DHPR demonstrated that the alpha(1)-beta complex was located in the large globular portion of the DHPR, and the N-terminal region of the beta subunit was extended to the leg-shaped protrusion of the DHPR, which includes the alpha(2)delta subunits. Our results propose a model in which the beta subunit may regulate ion channel function by acting as a hinge between alpha(1) and alpha(2)delta subunits of the DHPR.

Oral administration of synthetic retinoid Am80 (Tamibarotene) decreases brain beta-amyloid peptides in APP23 mice

The purpose of this study is to investigate whether a synthetic retinoid Am80 (tamibarotene) exhibits any improving effects on amyloid precursor protein (APP)23 mice, a model of Alzheimer's disease. Am80 was orally administered in feed to 20-week (5-month)-old APP23 mice at a dose of 0 (control) or 0.5 mg/kg/d for 14 weeks. The Am80 treatment reduced significantly the insoluble Abeta levels in brain, in particular Abeta(42), while it gave no apparent effects on the soluble Abeta levels. The results suggest that oral administration of Am80 may have potency to reduce the extracellular Abeta(42) of insoluble and possibly oligomeric or protofibril forms, which are related to the cause and/or progression of Alzheimer's disease. The Am80 treatment showed no significant effect on spatial learning and memory of APP23 mice by Morris water maze analysis. The main reason for the absence of significance seems based on the large deviation and some mice both in the treated and the non-treated groups would neither swim nor make efforts to reach the platform.

Evaluation by Bone Scintigraphy of Osteogenic Activity of Commercial Bioceramics (Porous β-TCP and HAp Particles) Subcutaneously Implanted in Rats

Osteogenic potential of biomaterials used in bone regenerative therapy has been mainly examined in an animal-implantation study. We have here evaluated the applicability of bone scintigraphy in imaging ectopic bone formation, especially its initial phase, by β-tricalcium phosphate (β-TCP) particles that were implanted in rat dorsal subcutaneous tissues. In implanted osteogenic osteosarcoma cells used as a positive control, osteoid formation was found by histological examination and bone scintigraphy using 99mTc- hydroxymethyl diphosphonate (HMDP) at 2 and 3 weeks post-implantation, respectively, while the microfocuscomputed tomography (μCT) system required further mineralization, which occurred at 4 weeks. Implantation of β-TCP particles alone induced only faint biomineralization inside the particles, which could be microscopically detected by calcein chelation at 2 weeks post-implantation, but not by other histological examinations (e.g., HE staining) or μCT. However, the bone scintigraphy successfully detected this microscopic change at 1 week. Implanted hydroxyapatite (HAp) particles alone used as a negative control did not induce mineralization at microscopic levels, and therefore nothing was detected by either calcein chelation or bone scintigraphy. In conclusion, the bone scintigraphic methodology, although exhibiting less quantitation and resolution, would be applicable as a non-invasive, highly sensitive methodology in detecting the initial, microscopic changes associated with mineralization.

Value of FDG-PET/CT findings revised using an anthropomorphic body phantom for the evaluation of tumor malignancy grade in small-sized lung adenocarcinomas: A multicenter study

7573

Background: The malignant behavior of small lung adenocarinomas (AD), which have been detected with increasing frequency recently, has not yet been clearly evaluated, and an understanding of this biological characteristic is vital for selecting the appropriate therapeutic strategy. We examined the malignancy grade of small lung ADs using FDG-PET/CT (PET), in addition to high-resolution CT (HRCT) and pathologic evaluation in a multicenter setting. Methods: A total of 204 patients with cT1N0M0 AD underwent PET and HRCT, followed by complete resection with lymph node dissection. The associations between components of bronchioloalveolar carcinoma (BAC) on pathologic examination and maximum standardized uptake value (maxSUV) on PET, ground-glass opacity (GGO) ratio and tumor disappearance rate (TDR) on HRCT were examined, and these findings were analyzed in relation to pathologic features and surgical outcomes. To reduce the errors in PET machines used for this analysis, maxSUV data were adjusted using an anthropomorphic body phantom of the NEMA standards (corrected maxSUV). Results: Examination of tumor aggressiveness based on the presence of lymphatic, vascular and pleural invasion, and of nodal metastasis, showed that maxSUV, BAC ratio, TDR, and GGO ratio, in the order, can reflect the malignancy grade. MaxSUV and BAC ratio were also valuable prognostic predictors of the disease-free survival. There were no significant differences in the values between maxSUV and corrected maxSUV. Although BAC ratio was significantly associated with maxSUV, GGO ratio and TDR (all p<0.0001), the degree of association with maxSUV (R2=0.2533) was weaker than that with GGO (R2=0.5843) ratio or TDR (R2=0.5123). Conclusions: A higher maxSUV reflects an aggressive malignant behavior of cT1N0M0 ADs, independently of BAC component. Assessment by PET in addition to HRCT is useful for selection of the appropriate treatment strategy for small lung AD.

[Table: see text]

No significant financial relationships to disclose.

Pharmacokinetics of 5-fluorouracil in elderly Japanese patients with cancer treated with S-1 (a combination of tegafur and dihydropyrimidine dehydrogenase inhibitor 5-chloro-2,4-dihydroxypyridine)

S-1 is an oral anticancer agent that combines tegafur, a prodrug of 5-fluorouracil (5-FU), and 5-chloro-2,4-dihydroxypyridine (CDHP), an inhibitor of dihydropyrimidine dehydrogenase. We examined the effects of aging on the pharmacokinetics of the components of S-1. The median area under the concentration-time curve (AUC) of active 5-FU did not significantly differ between 10 patients 75 years or older and 53 patients younger than 75 years (P = 0.598, Mann-Whitney U test). It is interesting to note that the median oral clearance of tegafur in patients 75 years or older was significantly lower than that in patients younger than 75 years (P = 0.011). Furthermore, the median AUC of CDHP was significantly higher in patients 75 years or older than in those younger than 75 years (P = 0.004). This effect was caused by reduced renal function in the elderly, because CDHP is excreted in the urine by glomerular filtration. The opposing effects of aging on the oral clearance of tegafur and the AUC of CDHP may offset each other, leading to unchanged systemic exposure of 5-FU.

Time-course changes in neural cell apoptosis in the rat fetal brain from dams treated with 6-mercaptopurine (6-MP)

6-Mercaptopurine (6-MP), one of the major drugs for the therapy of acute lymphoblastic leukemia and autoimmune diseases, is incorporated as thioguanine in nucleic acid and it induces cytotoxicity and fetotoxicity. In the present study, pregnant rats were treated with 50 mg/kg of 6-MP on 13 embryonic days (E), and fetuses were collected from 12 to 96 h after the treatment to examine the mechanism and time-course changes in neural cell death in the developing brain. The weights of fetal telencephalon and the thickness of the dorsal telencephalic wall of the fetuses were significantly reduced at 96 h. The number of pyknotic neural cells in the fetal telencephalon began to increase at 24 h, peaked at 36 h, and then gradually decreased toward 72 h. The nuclei of most of these pyknotic cells were stained positively by TUNEL method, which detects DNA fragmentation. Moreover, pyknotic cells were immunohistochemically positive for cleaved caspase-3, one of the key executioners of apoptosis, and the increased expression of the protein from 30 to 48 h was confirmed by using Western blot analysis. Also, electron microscopical features of the pyknotic cells showed ultrastructural characteristics of apoptosis. On the other hand, the number of mitotic and BrdU-positive neural cells in the telencephalon decreased from 30 to 72 h. These results suggest that 6-MP induced apoptotic cell death in neural cells in the rat fetal brain is probably due to cytotoxic action of 6-MP.

6-mercaptopurine (6-MP) induces p53-mediated apoptosis of neural progenitor cells in the developing fetal rodent brain

6-mercaptopurine (6-MP), a DNA-damaging agent, induces apoptosis of neural progenitor cells, and causes malformation in the fetal brain. The aim of the present study is to clarify the molecular pathway of 6-MP-induced apoptosis of neural progenitor cells in the fetal telencephalon of rats and mice. p53 protein is activated by DNA damage and induces apoptosis through either the intrinsic pathway involving the mitochondria or the extrinsic pathway triggered by death receptors. In this study, the expression of puma and cleaved caspase-9 proteins, which are specific intrinsic pathway factors, increased in the rat telencephalon after 6-MP treatment. 6-MP-induced apoptosis of neural progenitor cells was completely absent in p53-deficient mice. On the other hand, the expression of Fas protein, an extrinsic pathway factor, did not change throughout the experimental period in the rat telencephalon treated with 6-MP. The number of apoptotic neural progenitor cells was similar among Fas-mutated lpr/lpr and wild-type mice, suggesting that the Fas pathway does not play a significant role in 6-MP-induced apoptosis of neural progenitor cells. These results may suggest that the p53-mediated intrinsic pathway is essential for 6-MP-induced apoptosis of neural progenitor cells in the developing telencephalon of rats and mice.

Immunohistochemical Features of Dystrophic Axons in Papillon Dogs with Neuroaxonal Dystrophy

The immunohistochemical features of dystrophic axons in brain tissues of Papillon dogs with neuroaxonal dystrophy (NAD) were examined in comparison with 1 dog with cerebellar cortical abiotrophy (CCA) and a dog without neurologic signs. Histologically, many dystrophic axons were observed throughout the central nervous system of all dogs with NAD. These axonal changes were absent in the dog with CCA and in the control dog. Severe Purkinje cell loss was found in the dog with CCA, whereas the lesions were milder in all dogs with NAD. Immunohistochemically, the many dystrophic axons were positive for neurofilaments, tau, α/β-synuclein, HSP70, ubiquitin, synaptophysin, syntaxin-1, and synaptosomal-associated protein-25 (SNAP-25). A few dystrophic axons were positive for α-synuclein. In addition, these dystrophic axons, especially in the nucleus gracilis, cuneatus, olivaris, and spinal tract of the trigeminal nerve, were intensely immunopositive for the 3 calcium-binding proteins calretinin, calbindin, and parvalbumin. The accumulation of synapse-associated proteins in the dystrophic axons may indicate dysfunction of the synapse at the presynaptic portion. The accumulation of α-synuclein in the dystrophic axon and region-specific appearance of calcium-binding protein-positive spheroids are considered as unique features in NAD of Papillon dogs, providing the key to elucidate the pathogenesis.

Linkage between phosphorylation of the origin recognition complex and its ATP binding activity in Saccharomyces cerevisiae

The initiation of chromosomal DNA replication is tightly regulated to achieve genome replication just once per cell cycle and cyclin-dependent kinase (CDK) plays an important role in this process. Adenine nucleotides that bind to the origin recognition complex (ORC) are also suggested to be involved in this process. Of the six subunits of the Saccharomyces cerevisiae ORC (Orc1-6p), both Orc1p and Orc5p have ATP binding activity, and both Orc2p and Orc6p are phosphorylated by CDK in cells. In this study we constructed a series of yeast strains expressing phospho-mimetic mutants of Orc2p or Orc6p and found that expression of a Ser-188 mutant of Orc2p (Orc2-5Dp) delays G1-S transition and S phase progression and causes the accumulation of cells with 2C DNA content. Using antibody that specifically recognizes Ser-188-phosphorylated Orc2p, we showed that Ser-188 is phosphorylated by CDK in a cell cycle-regulated manner. Expression of Orc2-5Dp caused phosphorylation of Rad53p and inefficient loading of the six minichromosome maintenance proteins. These results suggest that the accumulation of cells with 2C DNA content is due to inefficient origin firing and induction of the cell cycle checkpoint response and that dephosphorylation of Ser-188 of Orc2p in late M or G1 phase may be involved in pre-RC formation. In vitro, a purified mutant ORC containing Orc2-5Dp lost Orc5p ATP binding activity. This is the first demonstration of a link between phosphorylation of the ORC and its ability to bind ATP, which may be important for the cell cycle-regulated initiation of DNA replication.

[Seeking "Etwas Neues"--from bioorganic chemistry to Alzheimer's disease]

Introduction to bioorganic chemistry by Prof. Kanaoka at the entrance of my research works affects greatly throughout the life afterward. Chemical modification studies of enzyme proteins taught me quality of chemical reactions. For example, triethyloxonium fluoroborate (Et3O+ BF4(-)), a Meerwein reagent, selectively reacted with a particular carboxyl group (Asp-177) in the substrate binding site of trypsin, even though the reaction was performed in aqueous solution. A series of ion channel studies intoxicate me how exciting the science works are. Purification of sodium channel protein from electric eels initiated the collaboration work to reveal total primary structure of the molecule, as an inaugurating work of ion channel molecules. Photoaffinity labeling proved to be an efficient method to elucidate ligand binding sites, such as TTX binding site within the sodium channel and the sites for calcium anatagonists in L-type calcium channels. Encounter with CD36 molecule expands our works to more pathobiochemical field. We revealed CD36, a class B scavenger receptor, is related to development of atherosclerosis by phagocytosis of ox-LDL in macrophages and even matured adipocytes. In microglia, however, CD36 plays clearance role of oligomeric beta-amyloid peptides in IL-4 activated type-2 microglia, suggesting the activation of type-2 microglia may be useful for developing a new method to treat or prevent from Alzheimer's disease.

IL-4-induced selective clearance of oligomeric beta-amyloid peptide(1-42) by rat primary type 2 microglia

A hallmark of immunopathology associated with Alzheimer's disease is the presence of activated microglia (MG) surrounding senile plaque deposition of beta-amyloid (Abeta) peptides. Abeta peptides are believed to be potent activators of MG, which leads to Alzheimer's disease pathology, but the role of MG subtypes in Abeta clearance still remains unclear. In this study, we found that IL-4 treatment of rat primary-type 2 MG enhanced uptake and degradation of oligomeric Abeta(1-42) (o-Abeta(1-42)). IL-4 treatment induced significant expression of the scavenger receptor CD36 and the Abeta-degrading enzymes neprilysin (NEP) and insulin-degrading enzyme (IDE) but reduced expression of certain other scavenger receptors. Of cytokines and stimulants tested, the anti-inflammatory cytokines IL-4 and IL-13 effectively enhanced CD36, NEP, and IDE. We demonstrated the CD36 contribution to IL-4-induced Abeta clearance: Chinese hamster ovary cells overexpressing CD36 exhibited marked, dose-dependent degradation of (125)I-labeled o-Abeta(1-42) compared with controls, the degradation being blocked by anti-CD36 Ab. Also, we found IL-4-induced clearance of o-Abeta(1-42) in type 2 MG from CD36-expressing WKY/NCrj rats but not in cells from SHR/NCrj rats with dysfunctional CD36 expression. NEP and IDE also contributed to IL-4-induced degradation of Abeta(1-42), because their inhibitors, thiorphan and insulin, respectively, significantly suppressed this activity. IL-4-stimulated uptake and degradation of o-Abeta(1-42) were selectively enhanced in type 2, but not type 1 MG that express CD40, which suggests that the two MG types may play different neuroimmunomodulating roles in the Abeta-overproducing brain. Thus, selective o-Abeta(1-42) clearance, which is induced by IL-4, may provide an additional focus for developing strategies to prevent and treat Alzheimer's disease.

A reliable method for the counting and control of single ions for single-dopant controlled devices

By 2016, transistor device size will be just 10 nm. However, a transistor that is doped at a typical concentration of 10(18) atoms cm(-3) has only one dopant atom in the active channel region. Therefore, it can be predicted that conventional doping methods such as ion implantation and thermal diffusion will not be available ten years from now. We have been developing a single-ion implantation (SII) method that enables us to implant dopant ions one-by-one into semiconductors until the desired number is reached. Here we report a simple but reliable method to control the number of single-dopant atoms by detecting the change in drain current induced by single-ion implantation. The drain current decreases in a stepwise fashion as a result of the clusters of displaced Si atoms created by every single-ion incidence. This result indicates that the single-ion detection method we have developed is capable of detecting single-ion incidence with 100% efficiency. Our method potentially could pave the way to future single-atom devices, including a solid-state quantum computer.

Frequency of nocturnal sudden death in patients with multiple system atrophy

Sudden death has been reported in patients with multiple system atrophy (MSA), although the frequency of this event has not been well delineated. We investigated the frequency and potential causes of sudden death in patients with MSA. During the 5-year observation period, 10 of 45 patients with probable MSA died. The causes of death included sudden death of unknown etiology (seven patients), aspiration pneumonia (one patient), asphyxia after vomiting (one patient), and lung cancer (one patient). The mean survival time of patients with sudden death was 63.0 +/- 24.7 months (range, 39-116 months). Among seven patients who experienced sudden death, six were found to have died during sleep. Among these patients, two had been treated with tracheostomy and three with continuous positive airway pressure (CPAP) or noninvasive positive pressure ventilation (NPPV) during sleep, suggesting that these treatments do not always prevent sudden death in patients with MSA. Nocturnal sudden death should be recognized as the most common mechanism of death in patients with MSA.

Localised radiotherapy for a ferret with possible anal sac apocrine adenocarcinoma

A seven-year-old, neutered male ferret was referred to our hospital with two perianal masses (2.4x3.0 and 2.4x3.5 cm, respectively) that had recurred after initial surgical excision. Complete resection of the masses was impossible as there was deep invasion along the rectum. On histopathology, the masses were diagnosed as apocrine adenocarcinoma possibly of anal gland origin based on tumour location. There was marked response to localised radiotherapy using an orthovoltage unit at 4 Gy, twice weekly. No visible mass was detectable after six doses of radiation. However, at that time, pleural effusion was diagnosed and radiotherapy was discontinued. Cytology of a sample of the pleural effusion suggested mesothelioma, and no obvious pulmonary metastasis of anal sac adenocarcinoma were identified on thoracic radiography. The ferret died at home on day 71 after the first admission.

Complementary Distributions of Amyloid-β and Neprilysin in the Brains of Dogs and Cats

Neprilysin is an amyloid-β-degrading enzyme localized in the brain parenchyma. The involvement of neprilysin in the pathogenesis of Alzheimer's disease has recently received much attention. We examined the localization of neprilysin and amyloid-β, as well as the activity of neprilysin, in the brains of dogs and cats of various ages to clarify the relationship between neprilysin activity and amyloid-β deposition. The distribution of neprilysin was almost identical in dogs and cats, being high in the striatum, globus pallidus, and substantia nigra, but very low in the cerebral cortex. The white matter and hippocampus were negative. Neprilysin activity in the brain regions in dogs and cats was ranked from high to low as follows: thalamus/striatum > cerebral cortex > hippocampus > white matter. Amyloid-β deposition was first detected at 7 and 10 years of age in dogs and cats, respectively, and both the quantity and frequency of deposition increased with age. In both species, amyloid-β deposition appeared in the cerebral cortex and the hippocampus. In summary, the localization of neprilysin and neprilysin activity, and that of amyloid-β, were complementary in the brains of dogs and cats.

Nicotine suppresses tunicamycin-induced, but not thapsigargin-induced, expression of GRP78 during ER stress-mediated apoptosis in PC12 cells

We previously reported that nicotine protected against tunicamycin (Tm)-induced ER stress-mediated apoptosis, but not thapsigargin (Tg)-induced apoptosis in PC12 cells. In the present study, we report that the expression of glucose-regulated protein 78 (GRP78) was suppressed by nicotine in Tm-treated PC12 cells. Interestingly, the GRP78 expression was not changed by nicotine in Tg-treated cells. Moreover, nicotine reduced the activation of caspase-12 in Tm-treated cells, but not in Tg-treated cells. These results suggest that nicotine prevented Tm-induced ER stress-mediated apoptosis by attenuating an early stage of Tm-induced ER stress. It was possible that the suppression of GRP78 expression by nicotine was achieved through the suppression of the Ire1-XBP1 and/or ATF6 pathways. We observed that nicotine suppressed the Tm-induced, but not Tg-induced, splicing of XBP1 mRNA, and also suppressed the Tm-induced, but not Tg-induced, production of cleaved ATF6 in PC12 cells. These results indicate that the suppression of Ire1-XBP1 and ATF6 pathways contributes to the suppression of GRP78 expression by nicotine in Tm-treated PC12 cells, suggesting that nicotine suppresses a common step upstream of both the Ire1-XBP1 and ATF6 pathways which are required for the expression of GRP78 during Tm-induced ER stress.

Congenital cystic adenomatoid-like malformation in a cynomolgus monkey (Macaca fascicularis)

Congenital cystic adenomatoid malformation (CCAM) is a developmental lung abnormality characterized by abnormal proliferation of mesenchymal elements and failure of bronchiolar structures to mature, ultimately resulting in the compression of normal pulmonary tissue and mediastinal shift with rapid expansion of cysts. Although various clinical and pathologic studies of CCAM in humans exist, CCAM has yet to be reported in animals, even in nonhuman primates. In the present study, histopathologic analyses of a neonatal cynomolgus monkey that died 17 days after birth revealed that normal lung architecture was replaced by disorganized overgrowths of cysts lined with simple cuboidal epithelium. The epithelium projected a few ciliates into the air spaces and produced mucus. To our knowledge, this is the first case study describing CCAM or a CCAM-like lesion in nonhuman primates.

Presence of perivenular elastic fibers in nonalcoholic steatohepatitis Fibrosis Stage III

Elastic fibers appear in extensive old fibrotic foci in general. We examined an association between hepatic fibrosis stage and the presence of perivenular elastic fibers in nonalcoholic steatohepatitis (NASH). A total of 48 liver needle biopsy specimens were used, taken from 48 cases with NASH. Fibrosis Stage (Brunt E, et al. Am. J. Gastroenterol. 1999) of the cases was as follows; six Fibrosis Stage I, twenty-two Fibrosis Stage II, and twenty Fibrosis Stage III. We examined Orcein stain sections in all of the liver needle biopsy specimens. In all twenty Fibrosis Stage III cases, perivenular elastic fiber bundles were observed. In contrast, perivenular elastic fibers were detected only in one of the six Fibrosis Stage I and two of the twenty-two Fibrosis Stage II cases. In liver needle biopsy specimens of NASH, detection of perivenular elastic fibers is useful in deciding Fibrosis Stage III.

Monoclonal antibody against rat podocyte-derived macrophagic cells reacts with crescent-forming cells in an experimental model

The origin of crescent-forming cells in crescentic glomerulonephritis has not been clarified in spite of the application of monoclonal antibodies (mAbs) against glomerular epithelial cells or monocytes/macrophages. This study was undertaken to characterize the cellular composition of crescents using a new marker, mAb OS-3, produced against macrophagic cells derived from podocytes in normal rat glomerular culture. Monoclonal antibody OS-3 was confirmed to be reactive with some normal epithelial cells of Bowman's capsule. Female Wistar Kyoto rats were injected with rabbit antiglomerular basement membrane (GBM) serum and killed at 2 h, 1, 3, 7, 14 days and 2 months, respectively. The mAb OS-3-positive cells were segmentally observed in glomeruli at 3 days, increased at 14 days, but decreased at 2 months. These cells lacked reactivity with antipodocalyxin in double immunofluorescence (IF) staining. In immunoelectron microscopy of a glomerulus on day 3 and 7, however, reaction products were observed within cells located on the outer surface of the GBM, which were considered to be podocyte in terms of its localization. In conclusion, we have shown a possibility that damaged podocytes partly constitute crescent-forming cells with phenotypic changes, visualized by positive staining with mAb OS-3. We propose a novel concept of crescent formation, suggesting that crescents may be partly composed of phenotypically changed cells, which could not be detected by typical markers for glomerular epithelial cells or monocytes/macrophages.