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Shinichiro Takayama

Publications and source records attributed to Shinichiro Takayama.

11 recordsLinked to original sources
PubMed2005

Specific expression of an HNK-1 carbohydrate epitope and NCAM on femoral nerve Schwann cells in mice.

Schwann cells are glial cells of the peripheral nervous system. There are two known subtypes of Schwann cells: those that are myelin-forming; and those that are non-myelin-forming. In this study, we looked at the expression of cell adhesion molecules in Schwann cells to determine whether other subtypes might exist. We used immunohistological analysis of femoral nerve segments containing sensory and motor fascicles, stained with anti-HNK-1, M6749 and anti-neural cell adhesion molecule (NCAM) monoclonal antibodies. Anti-HNK-1 and M6749 were positive in the motor fascicle, while anti-NCAM was positive in the sensory fascicle. Immunoblot analysis with the anti-HNK-1 and M6749 antibodies showed stronger immunoreactivity in the motor fraction than in the sensory fraction in the 100 kDa band. With the anti-NCAM antibody, the 140 and 120 kDa bands were seen in the sensory fascicle fraction, but not in the motor fascicle fraction. HNK-1-positive-cells were seen in motor fascicles 7 days after transection. However, the level of immunoreactivity diminished at 14 days, and no immunoreactivity was seen at 21 days. NCAM-positive cells were not observed 3 days after transection. In development, HNK-1-positive-cells and NCAM-positive cells were seen after P-21. These results suggest that the Schwann cells from the motor and the sensory fascicles have different subtypes. The motor and sensory Schwann cells may play different roles and function in a different way during peripheral nerve regeneration. In addition, there could be more stages of Schwann cell differentiation than previously thought; it is possible that myelin-forming Schwann cells differentiate into HNK-1-positive-cells (motor myelin-forming Schwann cells) and HNK-1-negative-cells (sensory myelin-forming Schwann cells), and non-myelin-forming Schwann cells differentiate into NCAM-positive cells (sensory non-myelin-forming Schwann cells) and NCAM-negative cells (autonomic non-myelin-forming Schwann cells).

Animals↗
PubMed2005

Chorea and Broca aphasia induced by diabetic ketoacidosis in a type 1 diabetic patient diagnosed as Moyamoya disease.

We here report one case of hemichorea and Broca aphasia occurred with diabetic ketoacidosis. A 20-year-old woman with type 1 diabetes mellitus had experienced diabetic ketoacidosis fourth time after the onset of diabetes. At the third ketoacidotic episode, the patient was admitted to our hospital for the first time to show hemichorea of the left extremities. Brain computed tomography (CT) demonstrated a high-density area in the right caudate head and low-density area in the right putamen. Magnetic resonance angiography (MRA) demonstrated a stenosis at the root of the bilateral middle and anterior cerebral arteries. The hemichorea disappeared within 3 days. At the fourth ketoacidotic episode, not hemichorea but unconsciousness was there for 2 days even after ketoacidosis disappeared. After the unconscious state, Broca aphasia was demonstrated for 15 days. The cerebral angiography showed a finding compatible to Moyamoya disease. These findings support that chorea and Broca aphasia induced by diabetic ketoacidosis was developed in addition to blood vessel abnormalities such as Moyamoya disease. We suggest that poorly controlled diabetic patients with hemichorea should undergo cerebral angiography.

Adult↗
PubMed2005

Increased incidence of hepatic insulin-sensitizing substance (HISS)-dependent insulin resistance in female rats prenatally exposed to ethanol.

Insulin causes the release of the hepatic insulin-sensitizing substance (HISS) from the liver. Hepatic parasympathetic nerves play a permissive role in the release of HISS. HISS-dependent insulin resistance (HDIR) occurs in the absence of HISS. Fetal ethanol exposure has been shown to cause dose-dependent HDIR in adult male rat offspring. Since female offspring are more severely affected by in utero ethanol toxicity, we hypothesized that fetal alcohol exposure causes higher incidence and more severe HDIR in adult female offspring. Adult female rat offspring prenatally exposed to different concentrations of ethanol (0%, 15%, and 20%) were tested for insulin sensitivity using the rapid insulin sensitivity test (RIST). The RIST index was significantly reduced in the 15% (134.1 +/- 16.1 mg/kg) and the 20% (98.7 +/- 9.7 mg/kg) group compared with the 0% (220.9 +/- 27.6 mg/kg) group. Administration of atropine produced significant additional HDIR in the 15% group (82.9 +/- 14.5 mg/kg) but not the 20% group (83.8 +/- 20.5 mg/kg) indicating complete HDIR had been produced in this group, contrary to the adult male offspring in a previous study. The results are consistent with the hypothesis that adult-female offspring are more severely affected by in utero ethanol exposure compared with adult-male offspring.

Animals↗
PubMed2004

Effect of number of fascicle on axonal regeneration in cable grafts.

The effect of number of fascicles on axonal regeneration in cable grafts was examined in the rat cable graft model. The study comprised three experimental groups: the 5f-group, which received 5 fascicles, larger than the host; the 3f-group, in which the total area of the graft fascicles was similar to that of the host; and the 1f-group, which received one fascicle cable graft, smaller in diameter than the host nerve. At the graft segment, well-myelinated fibers were observed both inside and outside the graft fascicles. The three groups showed no difference in morphometric and functional assessment, suggesting that the fibers which regenerated through the outside of the graft might be effectively induced into the distal host. The disproportionate enlargement of the graft fascicle of the 1f-group also increased the fibers passing through it. These findings suggest that a small number of fascicles can induce a larger population of regenerated fibers in the 20-mm cable graft model.

Anastomosis, Surgical↗
PubMed2004

Open repair of the ulnar disruption of the triangular fibrocartilage complex with double three-dimensional mattress suturing technique.

Open repair technique of the ulnar disruption of the triangular fibrocartilage complex is described. This technique is indicated for a fresh or a relatively fresh (less than 1 year after the initial injury) ulnar foveal detachment tear, horizontal tear, and proximal slit tear of the triangular fibrocartilage complex, all of which are accompanied by severe dorsal, palmar, or multidirectional instability of the distal radioulnar joint. A chronic tear greater than 1 year from initial injury and a fresh triangular fibrocartilage complex tear without distal radioulnar joint instability, such as central slit tear, are excluded from our indications. A dorsal C-shaped skin incision, a longitudinal incision of the radial edge of the extensor carpi ulnaris subsheath and the dorsal distal radioulnar joint capsule, exposes the distal radioulnar joint. A small, 5-mm longitudinal incision at the origin of the radioulnar ligament exposes its fovea detachment and/or the proximal slit tear of the triangular fibrocartilage complex. The disrupted radioulnar ligament is sutured in a pullout fashion to the ulna with a 3-dimensional double mattress technique through 2 bone tunnels that is precisely made at the central portion of the fovea with 1.2-mm K-wire. An additional horizontal mattress suture is used for closure of the small incision made at the radioulnar ligament, then the extensor carpi ulnaris is repaired. This open-repair technique is complex and requires precise technical skills; however, early results have been more rewarding than the conservative treatment.

Journal Article↗
PubMed2003

MR imaging in the diagnosis of denervated and reinnervated skeletal muscles: experimental study in rats.

PURPOSE: To describe the magnetic resonance (MR) imaging findings of denervation and reinnervation of skeletal muscles in rats. MATERIALS AND METHODS: The posterior tibial nerve was transected in 48 rats (nerve section group) and was repaired just after transection in another 48 rats (nerve repair group). At 2, 4, 6, and 8 weeks after surgery, changes in the area and signal intensity of the gastrocnemius muscle on T1- and T2-weighted MR images in vivo (four rats in each group) and T1s and T2s were analyzed in vitro in both groups (20 rats each) and compared with electromyographic findings. Water volume content and extracellular fluid space of the muscle in vitro were also examined in both groups (24 rats each). Four rats were used as controls for in vitro analysis. RESULTS: At T2-weighted MR imaging, the muscle showed continuously high signal intensity in the nerve section group. In the nerve repair group, the signal intensity was high until 4 weeks, when it recovered. Increases in signal intensity on T2-weighted MR images and T2s were seen in the nerve section group throughout the study period. In the nerve repair group, increased signal intensity on T2-weighted MR images was noted at 2 and 4 weeks and significantly returned to normal at 6 weeks (P <.014), just after the detection of the M wave at electromyography. T2 increased at 2 weeks, then decreased significantly at 4 weeks (P =.012). Extracellular fluid space significantly increased in the nerve section group at all measurement times and in the nerve repair group at 2 and 4 weeks, then it decreased after 6 weeks (P <.003), which is parallel to the change in signal intensity on T2-weighted MR images, although there was little change in total water volume content in either group. CONCLUSION: Changes in signal intensity on T2-weighted MR images that are related to denervation may result from an increase of extracellular fluid space. MR imaging clearly demonstrates that changes in rat skeletal muscle are reversed when the nerve heals and reinnervation proceeds.

Animals↗
PubMed2003

A case of pseudarthrosis of the capitate.

Pseudarthrosis of the capitate bone is extremely rare. In this case, the injury and pseudarthrosis was so old, the bone with a nutrient vessel was grafted, and bone union and excellent results are obtained.

Adult↗
PubMed2002

Traction injury of common peroneal nerve associated with multiple ligamentous rupture of the knee: a case report.

We report on a case of a 19-year-old male student who sustained a hyperextension injury to his left knee while playing rugby, which resulted in a traction injury of the common peroneal nerve and multiple ligamentous injuries at the knee joint. The damaged part of the common peroneal nerve was resected, and an end-to-end suture was performed, because the gap between the nerve ends was small enough to allow closure with little mobilization. Now, 2.5 years after the surgery, the patient shows remarkable recovery. This result suggests that end-to-end suture is an ideal procedure for nerve traction injury, if the nerve ends can be closed without tension, without excessive flexion of the adjacent joint.

Adult↗
PubMed2002

An experimental study on the perineurial window.

Neurological symptoms of herniated nerve fibers resulting from limited perineurial injury from sharp materials such as needles have become a recent topic in clinical practice. However, the mechanism of this disorder, which is known as a perineurial window, has not been clarified. To investigate the mechanism of nerve damage in the perineurial window, we designed small (1-mm length) and large (5-mm length) perineurial windows using tibial nerves of Wistar rats. In the 1-mm group, a marked hernia of the endoneurial contents developed soon and decreased in size with time, but protrusion of nerve fibers was still observed after 12 weeks. Nerve fibers in both the herniated portion and under the edge of the window were damaged. Even after 12 weeks, regeneration of the nerve fibers and the perineurium was incomplete. In contrast, in the 5-mm group, the initial endoneurial edema was remarkable, but herniated nerve fibers were not seen after 12 weeks. Neurological impairment in the 5-mm group was marked in the early stage but rapidly recovered. The repair of the perineurium and nerve fibers in the 1-mm group was slower than in the 5-mm group. Persistent neurological symptoms in the perineurial window appeared to be more closely associated with entrapment of nerve fibers at the window edge rather than with disruption of endoneurial homeostasis.

Animals↗
PubMed2002

Modified abductor digiti minimi opponensplasty in congenital hypoplastic thumb with laxity of metacarpophalangeal joint.

The abductor digiti minimi (ADM) opponensplasty is used widely as a standard technique of opponensplasty for congenital hypoplastic thumb. Functional results, however, are not always satisfactory in cases of marked laxity of the thumb metacarpophalangeal (MP) joint. The authors have developed a modified procedure of ADM opponensplasty to stabilize the thumb MP joint and to obtain appropriate opponens function. The first step of their modification is to retain the maximum length of transferred ADM muscle. The origin of the ADM is shifted radially and is reattached to the transverse carpal ligament. In our modification the ADM tendon is passed underneath the extensor pollicis longus tendon and is sutured to the adductor pollicis tendon at the ulnar side of the thumb MP joint. By this modified anchoring point the transferred ADM tendon runs across the ulnar side of the thumb MP joint and is expected to act as if it were an ulnar collateral ligament.

Journal Article↗