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Biomedical subjects

H Ohuchi

Publications and source records attributed to H Ohuchi.

At least 109 records · Page 6Linked to original sources
PubMed1994

Involvement of androgen-induced growth factor (FGF-8) gene in mouse embryogenesis and morphogenesis.

Androgen-induced growth factor (AIGF/FGF-8) has purified from a mouse mammary carcinoma cell line and its cDNA cloning revealed that AIGF is the eighth member of the fibroblast growth factor family. To clarify a biological role of FGF-8, Northern blot analysis of various adult tissues was carried out, but no expression was found. However, whole mount in situ hybridization of 7.5- to 14.5-day gestation (E7.5-14.5) embryos revealed six predominant expression domains: [1]primitive streak region (E7.5-9.75); [2]midbrain-hindbrain border (E8.0-10.5); [3]rostral forebrain (E8.0-10.5); [4]limb ectoderm and apical ectodermal ridge (E9.25-13.5); [5]nasal placode and epithelium (E9.5-12.5); and [6]branchial arch ectoderm (E8.5-11.5). The embryonic expression pattern suggests a unique role of FGF-8 in mouse development, especially in gastrulation, brain development, and limb and facial morphogenesis.

Animals↗
PubMed1994

Regional expression of the Cwnt-4 gene in developing chick central nervous system in relationship to the diencephalic neuromere D2 and a dorsal domain of the spinal cord.

Members of the Wnt gene family code for cysteine-rich, secreted proteins, which are differentially expressed in the developing brain and possibly act as an intercellular signaling molecule. A Wnt gene, e.g., Wnt-1 is known to be essential for specification of the midbrain cell fate. Since other members of the Wnt genes are likely to be also involved in development of the brain, we searched chick Wnt members expressing in specific domains of the brain. We found several novel Wnt members expressing specifically in the central nervous system of chick embryos. One of the genes was intensely expressed in a segment of the diencephalon at stages 14 and 20 and in a dorsal region of the spinal cord at stage 20. Although the expression patterns differ from those of mouse or Xenopus Wnt-4, the gene is highly homologous to the mouse or frog Wnt-4. Thus, we designated the gene as Cwnt-4 (chick Wnt-4). Our results suggested that Cwnt-4 is involved in segmentation of the forebrain into the neuromere D2 and in differentiation of the dorsal region of the spinal cord.

Amino Acid Sequence↗
PubMed1994

Expression patterns of two fibroblast growth factor receptor genes during early chick eye development.

The expression patterns of two distinct types of fibroblast growth factor receptor (FGFR) genes, FGFR1 and FGFR2, were compared during early chick eye development. In situ hybridization was performed with riboprobes synthesized from cDNA fragments of FGFRs cloned by the polymerase chain reaction method. FGFR1 was expressed in the prospective lens, neural retina, pigment epithelium and mandibular mesenchyme. In contrast, FGFR2 was expressed predominantly in the periocular mesenchyme of a 2.5 day-old embryo. In the 5.5-day-old embryo, transcripts of FGFR2 were detected in the prospective corneal epithelium. The results suggest that expression patterns of FGFR1 and FGFR2 are complementary and ligands of each FGFR might be involved differentially in early chick eye development. It is concluded that the action of FGFs on pigment epithelium and lens cells reported so far, probably occurs through FGFR1, and both types of FGFR are involved in head mesenchymal development.

Animals↗
PubMed1994

Protective effect of heparin on renal glomerular anionic sites of streptozotocin-injected rats.

Albuminuria at the rate of 500 micrograms/24 h was observed in rats treated with 50 mg/kg body wt. i.v. streptozotocin (STZ). When STZ was combined with heparin, administered twice daily (250 IU/kg subcutaneous injection) after 24 h following STZ injection, the daily urinary albumin excretion (U-AE) was less than half the amount found in non-heparinized rats (280.3 micrograms/24 h). The observation period in both instances was 8 weeks. When animals were permitted to develop albuminuria over the first 4 weeks, subsequent heparin administration for another 4 weeks lowered U-AE from 500 micrograms/24 h to less than half the amount (227.8 micrograms/24 h). A significantly negative correlation (P < 0.001) existed between U-AE and the number of anionic sites (AS) in the lamina rara externa of glomerular basement membranes, as visualized by electron microscopy. The number of AS per 1000 nm in STZ-injected rats (15.5 +/- 0.2) was lower than that in control rats (23.1 +/- 0.6); however, in heparinized animals, regardless of STZ, the values were not significantly different from normal. Heparin by itself had no effect on the number of AS in normal rats. All STZ-injected animals became hyperglycemic (400-550 mg/dl), but received no insulin. Heparin had no effect on plasma glucose levels. From these results, it is concluded that heparin suppressed both of an increase in U-AE and a decrease in AS count of glomerular basement membranes in STZ-injected rats.

Albuminuria↗
PubMed1994

Algorithm of the noninvasive diagnosis method on the atherosclerosis by ultrasonic Doppler effect.

Previously we proposed Acoustical Imaging and Processing Method to measure the viscoelastic property of the blood vessels of a canine and the related materials using Ultrasonic Doppler Effect Measurement. Furthermore, its theoretical foundation was presented. In this paper, this method is applied to measure the viscoelastic mechanical property, that is, the mechanical degradation of human blood vessels by a percutaneous noninvasive method. Based on these results, we proposed the algorithm of the noninvasive estimation method on the viscoelastic mechanical property of the blood vessel by using Doppler Effect Sensor. This method makes it possible to discriminate the blood vessel with arteriosclerosis from a normal blood vessel. Clinical applications were successfully performed using our developed computer software based on our proposed algorithm.

Algorithms↗
PubMed1993

A chicken homeobox gene related to Drosophila paired is predominantly expressed in the developing limb.

We identified a homeobox-containing gene, Prx-1, isolated from the chick limb bud cDNA library. The homeodomain sequence is related to Drosophila paired and goose-berry and mouse Pax-3, Pax-6, and Pax-7. The deduced amino acid sequence of the Prx-1 gene product reveals the absence of a paired-box sequence and extensive similarity to mouse S8 and MHox homeodomain proteins, thus constituting a new class of homeobox gene. Using an in situ hybridization method, the Prx-1 gene is shown to be expressed predominantly in the limb bud and visceral arches. At early stages of limb development, distal mesodermal cells express the homeobox gene with an apparent gradient along the proximal-distal axis. The signal is absent in the apical and nonridge ectoderm. Removal of the apical ectodermal ridge had no apparent effect on the subsequent expression of Prx-1 in the limb mesenchyme. The Prx-1-expressing cells are later confined to the interdigital and perichondrial regions. The Prx-1 transcripts are also detectable in the mesenchyme of the visceral arches and facial primordia subjacent to the ectoderm. The Prx-1 gene is weakly expressed in somites and condensing vertebrae. No signal is detectable in neural tube and ectodermal epithelium. These results suggest that the Prx-1 homeodomain protein is involved in the differentiation of bone, muscle, and other tissues of mesodermal origin during limb development.

Amino Acid Sequence↗
PubMed1993

A mutation in the Pax-6 gene in rat small eye is associated with impaired migration of midbrain crest cells.

The rat small eye strain (rSey) lacks eyes and nose in the homozygote, and is similar to the mouse Sey strain with mutations in the Pax-6 gene. We isolated Pax-6 cDNA clones from an rSey homozygote library, and found an internal deletion of about 600 basepairs in the serine/threonine-rich domain. At the genomic level, a single base (G) insertion in an exon generates an abnormal 5' donor splice site, thereby producing the truncated mRNA. Anterior midbrain crest cells in the homozygous rSey embryos reached the eye rudiments but did not migrate any further to the nasal rudiments, suggesting that the Pax-6 gene is involved in conducting migration of neural crest cells from the anterior midbrain.

Alternative Splicing↗
PubMed1993

Differential expression of three chick FGF receptor genes, FGFR1, FGFR2 and FGFR3, in limb and feather development.

Expression patterns of three fibroblast growth factor receptor genes, FGFR1 (cek1), FGFR2 (cek3) and FGFR3 (cek2), were observed in limb and feather morphogenesis. Expression of FGFR1 was observed in the mesoderm of limb bud, in the mesenchyme just underneath the feather placode, and then in the anterior mesenchyme of the feather bud. While expression of FGFR2 was observed in both surface ectoderm and mesenchymal aggregates corresponding to the future bones of the limb, the mesenchyme between the feather placode, and surface ectoderm of feather buds. Expression of FGFR3 was observed rather ubiquitously over mesoderm of limb and feather buds. Differential expression of these FGF receptor genes suggested that differential roles of these receptors in epithelia-mesenchymal interactions of limb and feather morphogenesis.

Animals↗
PubMed1993

Expression patterns of the activin receptor IIA and IIB genes during chick limb development.

Activin is known to induce axial mesoderm during early development in Xenopus embryo. Activin receptor was recently identified to be a member of transmembrane serine/threonine kinase family. We have studied the role of activin-mediated signaling in the limb morphogenesis by identifying the target cells. We isolated cDNAs encoding chicken activin receptors, cARIIA and cARIIB, and examined their expression patterns during chick embryogenesis. The cARIIA gene is expressed in the apical ectoderm of the limb bud at stage 20-21, whereas the cARIIB gene is expressed uniformly in the limb mesenchyme. Expression of the cARIIA gene is confined to dorsal and ventral mesenchyme at stage 23, and later confined to precartilaginous cells. Transcripts of the cARIIA gene are found in developing neuroepithelium of spinal cord, brain and eye, surface ectoderm differentiating to epidermis, and myoblasts differentiating to muscle. The IIB receptor gene is highly expressed in the developing brain. These results suggest that the activins and their receptors are implicated in the limb development, especially, in differentiation of muscle, skin and bone.

Activin Receptors↗
PubMed1993

Hybrid concept on the mechanical test method of small caliber blood vessel.

A mechanical test on small caliber blood vessel is difficult because the strength is very low and the dimension is very small. In the present paper a multifunctional axial test apparatus design is proposed. This has the characteristics such that the load cell and the environmental container for the specimen are built up in terms of cassette, respectively, and thus both are easy to equip and take off, that is, easy to replace. Also, the test methodology by internal pressure for small caliber blood vessels has been proposed. By using both of these methodologies, the characteristics of the mechanical behavior of small caliber blood vessels, such as compliance, stress relaxation, and viscoelastic property have been clarified. An attempt has been made on the application of this method to a clinical case.

Anastomosis, Surgical↗
PubMed1993

[Expression pattern of fibroblast growth factor receptor 2 gene during chick eye development].

To reveal the expression pattern of fibroblast growth factor receptor 2 (FGFR2) gene during chick eye development, in situ hybridization was performed on sections of chick embryos from stage 8 to 28. At stage 8 and 10 when the primary optic vesicle is formed, transcripts of FGFR2 were observed diffusely over the embryo. At stage 17 when the optic cup develops and afterwards, FGFR2 expression was predominantly detected in the periocular mesenchyme and parts of the diencephalon. At stage 28, FGFR2 was also expressed in the corneal epithelium and endothelium, but it was not observed in blood cells or the endothelium of the cephalic vein. FGFR2 expression was not observed in the lens or the optic cup where FGFR1 is expressed. I suggest that FGFR2 expression is involved in development of the corneal epithelium and the periocular mesenchyme, which is derived from the cephalic neural crest cells.

Animals↗
PubMed1993

[Expression pattern of fibroblast growth factor receptor 1 gene during chick eye development].

To reveal the expression pattern of fibroblast growth factor receptor 1 (FGFR1) gene during chick eye development, in situ hybridization was performed on sections of chick embryo from stage 8 to 28. At stage 8 and 10, transcripts of FGFR1 were observed over the whole embryo and they were located at the optic cup, the lens vesicle, the orbital mesenchyme and the neuroepithelium of the diencephalon at stage 17. In the inner layer of the optic cup at stage 21, the expression was restricted to the anterior portion. It was suggested that FGFR1 expression was involved in chick eye development, especially in determination of anterior-posterior axis of the eye.

Animals↗
PubMed1992

Expression pattern of the activin receptor type IIA gene during differentiation of chick neural tissues, muscle and skin.

To elucidate target cells of activins during embryogenesis we isolated cDNAs of chick activin receptor type II (cActR-II) and studied expression patterns of the cActR-II gene by in situ hybridization. Transcripts of cActR-II were observed in neuroectoderm developing to spinal cord, brain and eyes, in surface ectoderm differentiating to epidermis, and in myotomes differentiating to muscles. The expression patterns of cActR-II suggest that activin and its receptor are involved in differentiation of chick neural tissues, muscle and skin after inducing the dorsal mesoderm.

Activin Receptors↗
PubMed1992

[One-staged repair for coarctation of the aorta and annuloaortic ectasia with severe aortic regurgitation in a patient with Turner syndrome].

A 27-year-old woman with Turner syndrome was admitted to NCVC for congestive heart failure. 2-D echocardiography and magnetic resonance imaging (MRI) disclosed annuloaortic ectasia with severe aortic regurgitation and coarctation of the aorta. One staged operation by a modified Bentall procedure and extra-anatomical bypass grafting from the ascending aorta to the infrarenal abdominal aorta was successfully performed. The postoperative course was uneventful. The pressure gradient between upper and lower extremities decreased as to be 30 mmHg compared with preoperative 60 mmHg.

Adult↗
PubMed1991

Acoustical imaging and processing of blood vessel and the related materials using ultrasound Doppler effect.

In the present paper a method is proposed to measure the degree of the degradation of the elasticity in natural blood vessel and the related materials by using ultrasound Doppler effect. It was found that the deformation rate and its acceleration in the radial direction of the blood vessel can be detected by acoustical imaging and processing using this method. These results were proven to correspond to the degree of the degradation of the elasticity, that is, the degree of viscoelasticity in the blood vessel from the wave versus time pattern detected and its simple analysis. This method was applied to predicting the arteriosclerosis of blood vessels of humans by acoustical imaging and processing uninvadedly, as the characteristics of viscoelasticity in blood vessels.

Algorithms↗
PubMed1991

[Ventricular septation combined with arterial switch for a patient with double inlet left ventricle with right sided rudimentary right ventricle and ventriculoarterial discordance].

A 5-year-old boy with double inlet left ventricle and ventriculoarterial discordance (SDD type) underwent ventricular septation with arterial switch procedure. Previously he had received pulmonary arterial banding at 3 months-old. Preoperative cardiac catheterization revealed Qp/Qs 1.26, Pp/Ps 0.19 and LVEDV was 315% of normal (as left ventricle). Arterial switch with Lecompte modification was performed in order to separate ventricle with straight patch could be done. Post operative course was uneventful and patient was extubated 4 post operative day. These procedures had employed in this patient as follows; 1) systemic ventricle could be constructed with morphological left ventricle with mitral valve. 2) left ventricular outflow tract stenosis due to ventricular outlet foramen occasionally observed in conventional procedure such as intraventricular rerouting could be prevented, and 3) ventricular septation could be easy and simple with straight patch.

Aorta↗
PubMed1991

Effects of pulsatile flow pattern and each stage of pressure increasing, constant and decreasing, respectively upon inelastic deformation of blood vessel.

The aim of this study is to elucidate the relation of the inelastic expansive deformation of natural blood vessel and the degradation of elasticity to the time pattern of circulating pulsatile pressure flow. When pulsatile pressure amplitude (delta P = Pmax - Pmin) becomes smaller due to Pmin increasing, the blood vessel is subject to creep deformation. In this sense, pulsating pressure will play a role in avoiding creep effect. Fluctuation of maximum pressure Pmax will induce the increase of inelastic deformation and the decrease of rigidity of the blood vessel. The inelastic deformation and the decrease of rigidity in blood vessel is induced at the stage of pressure amplitude rising from a lower one to a higher, but not during pressure amplitude (delta P) kept constant nor at the pressure amplitude decreasing stage. In order to reduce the degradation of mechanical properties of blood vessel, it may be effective to avoid the increase of Pmin and the variability of Pmax.

Biomechanical Phenomena↗