Biomedical subjects

Seiichiro Okajima

Publications and source records attributed to Seiichiro Okajima.

10 recordsLinked to original sources

PubMed2006

Surgical treatment for spinal accessory nerve injury.

We report on the surgical results of spinal accessory nerve injuries between 1992-2003. We operated on 10 patients (9 female, and 1 male) who had injuries of the spinal accessory nerve. All injuries were iatrogenic. The mean age of patients was 39.2 years (range, 20-57 years). The average interval between date of injury and surgery was 7 months (range, 4-12 months). All patients had stiffness and pain in the shoulder girdle. The average active abduction of the shoulder joint was 79.5 degrees (range, 60-100 degrees ) before surgery. End-to-end repairs were performed in 7 cases, and graft repairs were indicated in 3 cases. The mean follow-up period was 18.4 months (range, 8-36 months). The average active abduction of the shoulder joint was 171 degrees (range, 140-180 degrees ) at time of final follow-up.

Accessory Nerve↗

PubMed2005

Expression of tight and gap junctional proteins in the perineurial window model of the rat sciatic nerve.

Limited perineurial injury, known as a perineurial window, can lead to neuropathic pain. This article hypothesizes that the recovery of the perineurium is associated with the intercellular junctional proteins. It analyzes the expressions of occludin, ZO-1, and connexin 43 by immunoconfocal microscopy. Seven days after injury, immunoreactivities for occludin and ZO-1 were observed, although there was no connexin 43 detected. Then, 21 days after injury, immunoreactivity for connexin 43 were observed. These results indicate that recovery of the perineurium is associated with the intercellular junctional proteins and that the recovery of gap junctions is delayed compared with that of tight junctions.

Animals↗

PubMed2004

Regional differences in blood-nerve barrier function and tight-junction protein expression within the rat dorsal root ganglion.

To elucidate blood-nerve barrier function and tight-junction protein expression in the dorsal root ganglion (DRG), we analyzed the vascular permeability in the rat DRG by i.v. administration of fluorescent Evans-blue albumin (EBA) and compared it with the localization of claudin-1, claudin-5, and occludin by immunoconfocal microscopy. In the cell body-rich area within the DRG, extravascular leakage of EBA was noted and claudin-5 but neither claudin-1 nor occludin was detected. Conversely, in the nerve fiber-rich area within the DRG, no extravascular leakage of EBA was observed and both claudin-5 and occludin but no claudin-1 were detected in the blood vessel. These results demonstrate regional differences in the blood-nerve barrier function and tight-junction protein expression within the DRG.

Animals↗

PubMed2003

A novel marker for terminal Schwann cells, homocysteine-responsive ER-resident protein, as isolated by a single cell PCR-differential display.

Terminal Schwann cells (TSCs) that cover motor neuron terminals are known to play important roles in maintaining neuromuscular junctions, as well as in the repair process after nerve injury. However, molecular characteristics of TSCs remain unknown, because of the difficulties in analyzing them due to their paucity. We have established a method of selectively and efficiently collecting TSCs so that cDNA analysis can be done properly. The expression of 1-2% of whole mRNAs was compared between myelinating Schwann cells (MSCs) and TSCs, and it turned out that approximately one-third of the bands could be categorized as cell-type-specific bands. TSCs thus constitute a distinct entity from the viewpoint of gene expression. As one of the cDNA clones belonging to TSC-specific bands was identified homocysteine-responsive ER-resident protein (Herp), and in situ hybridization confirmed that Herp mRNA is expressed in TSCs on motor nerve terminals but not in MSCs, both in developing and adult rats. In conclusion, we have been able to identify Herp as a novel molecular marker for TSCs.

Animals↗

PubMed2003

Loss and recovery of the blood-nerve barrier in the rat sciatic nerve after crush injury are associated with expression of intercellular junctional proteins.

The blood-nerve barrier in peripheral nerves is important for maintaining the environment for axons. Breakdown of the barrier by nerve injury causes various pathologies. We hypothesized that the breakdown and recovery of the blood-nerve barrier after injury are associated with the changes in the expression of intercellular junctional proteins. To test this hypothesis, we induced crush injuries in the rat sciatic nerve by ligation and analyzed spatiotemporal changes of claudin-1, claudin-5, occludin, VE-cadherin, and connexin43 by immunoconfocal microscopy and morphometry and compared them with changes in the permeability of the blood-nerve barrier by intravenous and local administration of Evans blue-albumin (EBA). On day 1 after removal of the ligature EBA leaked into the connective tissue in the endoneurium and then the leakage gradually decreased and disappeared on day 7. On day 1 claudin-1, claudin-5, occludin, VE-cadherin, and connexin43 had totally disappeared from the perineurium and endoneurium. Thereafter, claudin-1, claudin-5, occludin, and VE-cadherin recovered from day 2, whereas connexin43 was redetected on day 5. These results indicate that the breakdown and following recovery of the blood-nerve barrier are closely associated with changes in the expression of claudins, occludin, VE-cadherin, and connexin43 and that the recovery time course is similar but nonidentical.

Animals↗

PubMed2002

Histological and electrophysiological analysis of the peripheral nerve allografts using an immunosuppressive agent.

In peripheral nerve allografts, use of an immunosuppressive agent is one of the ways of reducing nerve rejection. FK506 is a newly discovered substance, extracted from Streptomyces tsukubaensis, and has strong immunosuppressive effects. In the present study, immunosuppressive effects of FK 506 were examined using allografts of rat sciatic nerves. Good nerve regeneration was demonstrated through 12 weeks in this model. The immunosuppressed group gained weight over the course of the experiment. Another study was performed to observe the histological changes caused by ceasing the administration of FK506. Administration of FK506 was terminated 12 weeks after grafting. At 8 weeks after cessation, cellular infiltration and large unmyelinated axons were observed in the extended subperineurial space of grafts. At 12 weeks, histological characteristics of rejection were not observed. In the electrophysiological study, the temporal dispersions were recorded at 4 and 8 weeks. However, the normal electrophysiological waves were recorded at 12 weeks after cessation. It was concluded that FK506 is effective for preventing rejection of nerve allografts without any serious side effects on rats, and findings of total rejection of grafts were not recognized after ceasing the administration of FK 506. In peripheral nerve allografts, short-term administration of an immunosuppressive agent is sufficient to lead to good nerve regeneration.

Action Potentials↗

PubMed2002

Newly devised anterior portal technique for arthroscopic bankart repair using suture anchors.

Many techniques and instrument systems have been developed for performing arthroscopic Bankart repair using a suture anchor. The suture anchor procedure relies on a secure knot, which does not become entangled in the anterior portal. A newly devised anterior portal technique can solve this problem. We have used this technique for arthroscopic Bankart repair using suture anchor. This technique may be useful for any type of suture materials such as SLAP lesion.

Arthroscopy↗

PubMed2002

[Clinical application of PGA-tube for regeneration of intrapelvic nerves during extended surgery for intrapelvic recurrent rectal cancer].

For the regeneration of injured peripheral nerves, we have devised a PGA-tube that is composed of a tube of polyglycolic acid containing collagen sponge. This PGA-tube was applied clinically to reconstruct a peripheral nerve that had been resected during extended surgical resection of for intrapelvic recurrent rectal cancer. Four months after the surgical resection, the function of the left hip joint has improved remarkably, whereas the function had been lost just after the operation. It is suggested that the PGA-tube will be useful for regeneration of peripheral nerves that are resected during operation for intrapelvic malignancy.

Aged↗

PubMed1999

Insulin-like growth factor-I promotes nerve regeneration through a nerve graft in an experimental model of facial paralysis.

Among the pathological sequelae of facial paralysis is a paralytic eye. Apart from the psychological and aesthetic deficits, facial paralysis if left untreated can lead to dryness, ulceration and eventual blindness. Although numerous restorative microsurgical approaches have been introduced to address the sequelae of this problem, complete restoration of function to denervated facial muscles remains elusive.Utilizing the rat model of facial paralysis the present research has as an objective to examine a dual treatment approach. Specifically, this study combined the current microsurgical treatment of the cross-facial nerve graft with local administration of insulin-like growth factor I (IGF-I).The efficacy of this combined approach (cross-facial nerve graft + IGF-I) was assessed in the following ways: (a) behavior measurement of the blink response and (b) histomorphometry light and electron microscopy of the entire nerve graft. These data will help provide insight into the restoration of facial muscle function after trauma and assist in the future development of more potent treatment strategies.7he local adnünistration of IGF-I (50 micro g/ml) to the cross-facial nerve graft was found to restore the blink response faster and to strengthen the degree of eye closure. Light microscopy examination revealed that IGF-I significantly enhanced axonal regeneration within a nerve graft (a 22% increase in the mean number of axons), and increased the mean nerve fiber diameter and myelin thickness. Electron microscopy assessment of the nerve grafts demonstrated that the IGF-I treated grafts possessed a greater density of microtubules, which were evenly distributed within the axoplasm.

Journal Article↗

PubMedDate not supplied

Shoulder deformities in obstetric brachial plexus paralysis: a computed tomography study.

Obstetric brachial plexus palsy invariably involves the upper roots. If left untreated, characteristic deformities of the shoulder are common sequelae. The most objective way to investigate these shoulder deformities is computed tomographic (CT) scanning of bilateral upper limbs. In this study, specific measurements on CT scans of bilateral upper extremities were performed in a population of patients with obstetric brachial plexus palsy before and after reconstruction (nerve repairs and secondary procedures). The measurements showed that the restoration of external rotation and the scapula stabilization procedure correct the inclination of the humeral head, improve the joint congruency significantly, and decrease the winging of the scapula, thus improving the kinetics of the shoulder. Periodic CT measurement is an objective method of measuring the changes at the shoulder joint that occur over time during the natural evolution of the obstetric brachial plexus palsy lesion and of documenting the benefits of microsurgical intervention.

Brachial Plexus↗