Shigeki Hirano

Learn More
The Pax6 gene plays a developmental role in various metazoans as the master regulatory gene for eye patterning. Pax6 is also spatially regulated in particular regions of the neural tube. Because the amphioxus has no neuromeres, an understanding of Pax6 expression in the agnathans is crucial for an insight into the origin of neuromerism in the vertebrates.(More)
Due to the peculiar morphology of its preotic head, lampreys have long been treated as an intermediate animal which links amphioxus and gnathostomes. To reevaluate the segmental theory of classical comparative embryology, mesodermal development was observed in embryos of a lamprey, Lampetra japonica, by scanning electron microscopy and immunohistochemistry.(More)
Neural crest cells contribute extensively to vertebrate head morphogenesis and their origin is an important question to address in understanding the evolution of the craniate head. The distribution pattern of cephalic crest cells was examined in embryos of one of the living agnathan vertebrates, Lampetra japonica. The initial appearance of putative crest(More)
The development of peripheral nerves was studied in a Japanese marine lamprey, Lampetra japonica, in whole-mount and sectioned embryos from hatching until the earliest ammocoete. Nerve fibers were immunohistochemically stained with a monoclonal antibody against acetylated tubulin. Branchiomeric nerves first developed in a simple metamerical pattern, each(More)
The circuit changes that mediate parkinsonian tremor, while likely differing from those underlying akinesia and rigidity, are not precisely known. In this study, to identify a specific metabolic brain network associated with this disease manifestation, we used FDG PET to scan nine tremor dominant Parkinson's disease (PD) patients at baseline and during(More)
BACKGROUND Little is known as to whether or not the seven personality dimensions of Cloninger's theory, particularly the three character dimensions newly included in the theory, are independent of the states of depression. METHODS One hundred and eight patients with major depression filled out the Temperament and Character Inventory (TCI) before and after(More)
The lateral suprasylvian visual area (LS) is known to have numerous interconnections with visual cortical areas as well as with subcortical structures implicated in visually-guided behaviors. In contrast, little data is available regarding connections within the LS itself. In order to obtain information about intra-areal connections and to re-investigate LS(More)
Genes involved in late specification of the mandibular arch, the source of the vertebrate jaw, are expressed with similar patterns in the oral regions of chick and lamprey embryos. However, morphological comparisons indicate that apparently orthologous homeobox genes were expressed in different subdivisions of the ectomesenchyme in the two species.(More)
The purpose of this study was to investigate morphological characteristics of the synaptic relations of choline acetyltransferase (ChAT)-positive terminals that are made with a variety of post-synaptic profiles in the lateralis medialis-suprageniculate nuclear complex (LM-Sg) using ChAT, gamma-aminobutyric acid (GABA) and glutamate immunohistochemistry in(More)
We compared the metabolic and neurovascular effects of levodopa (LD) therapy for Parkinson's disease (PD). Eleven PD patients were scanned with both [15O]-H2O and [18F]-fluorodeoxyglucose positron emission tomography in the unmedicated state and during intravenous LD infusion. Images were used to quantify LD-mediated changes in the expression of motor- and(More)