Acetyl-L-carnitine enhances myelination of regenerated fibers of the lateral olfactory tract

It is well known that acetyl-L-carnitine (ALC) has various neuroprotective effects against neurodegenerative diseases. In addition, it has been reported that ALC facilitates myelination of regenerated axons after peripheral nerve injuries. We previously reported that spontaneous regeneration of the lateral olfactory tract (LOT), the main fiber tract of the central olfactory system, consistently occurred in newborn rats and a majority of these regenerated fibers were unmyelinated in neonatally LOT-transected young adult rats. To investigate the effects of ALC treatment on myelination in LOT, neonatal rats were treated with ALC after LOT transection. Immunohistochemistry for myelin basic protein showed more positive areas in ALC-treated rats than in control rats. Moreover, the number of myelinated axons of regenerated fibers was assessed using electron microscopy and was found to be statistically higher in ALC-treated rats compared to control rats. The study revealed that ALC accelerates myelination of regenerated fibers in neonatally LOT-injured young adult rats. (C) 2017 Elsevier B.V. All rights reserved.ArticleNEUROSCIENCE LETTERS.653:215-219(2017)journal articl

The Relationship of the Subclavius Muscle with Relevance to Venous Cannulation below the Clavicle

Introduction. The catheter “pinch-off syndrome” has been described to be secondary to crimping of the catheter between the clavicle and the first rib, as well as entrapment of the catheter at the site of penetration of the subclavius muscle. The lateral insertion technique has been recommended to prevent catheter pinch-off, but it is unknown if this technique can prevent entrapment by the subclavius muscle. We undertook this study to evaluate the anatomical relationship of the subclavius muscle and the subclavian vein. Methods. Twenty-eight adult cadavers were studied on both right and left sides. The adherence between the subclavian vein and subclavius muscle was subjectively assessed and the distance between the two structures was measured in mm. Results. The subclavius muscle and subclavian vein were tightly adherent in 72% of specimens, partly adherent in 14% with a mean distance of 4.5 mm and loosely connected in 14% with a mean distance of 6.1 mm. Conclusions. The anatomical relationship between the subclavius muscle and vein was very close in the majority of specimens, suggesting that the lateral insertion technique may not prevent penetration of the muscle, which may contribute to catheter pinch-off. The real-time ultrasound-guided technique may prevent penetration of the subclavius muscle

Functional correlation between olfaction and various sectioning of the lateral olfactory tract

信州大学博士（医学）・学位論文・平成24年3月31日授与（甲第915号）・関口泰之The lateral olfactory tract (LOT) is a central olfactory pathway, and efferent projections from the olfactory bulb are conveyed to the olfactory-related cortical structures via the LOT. The purpose of the present study is to determine the exact site of the LOT causing functional impairment in animals. After ablation of the right olfactory bulb, rats received rostrocaudal transection injuries on the left LOT at different levels between the olfactory bulb and the middle cerebral artery. Olfactory function of LOT-transected rats was studied by examining their olfactory ability to discriminate between the smell of water and cycloheximide solution, a strong repellent for rodents. Rats were divided into two groups based on their olfactory discriminative abilities. The olfaction positive (+) group achieved 83% +/- 1% correct responses and the distances of the LOT-transected sites from the middle cerebral artery of this group ranged between 0.8 and 2.4 mm (n = 8). The olfaction negative (-) group achieved 48% +/- 1% correct responses and the distances of the LOT-transected sites from the middle cerebral artery ranged between 2.5 and 4.2 mm (n = 10). From these data, we concluded that the site of the LOT critical for olfactory function is located approximately 2.5 mm from the middle cerebral artery. (c) 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.ArticleNEUROSCIENCE RESEARCH. 73(1):17-23 (2012)journal articl

Analysis of spontaneous regeneration of olfactory structures with emphasis on myelination and re-innervation of cortical areas

Regeneration of the lateral olfactory tract (LOT) occurs spontaneously after transection in developing rats. In neonatally LOT-transected rats, we observed a newly formed myelinated tract near the rhinal sulcus. The aim of this study was to analyze the precise re-innervated cortical areas and to demonstrate ectopic LOT myelination in neonatally LOT-transected rats. Neonatal rats were subjected to unilateral LOT transection and simultaneous injection of a retrograde fluorescent tracer into the posterior olfactory cortex to evaluate the degree of transection. After 8 weeks, bilateral olfactory bulbs of the rats were subjected to multiple injections of an anterograde neuronal tracer to determine the extent of the regenerated fibers. In the completely LOT-transected rats, the regenerated fibers were distributed in the anterior olfactory cortices: the anterior olfactory nucleus, the olfactory tubercle, and the rostral part of the piriform cortex. Ectopic myelination of LOT was evident immediately below the rhinal sulcus in the completely and incompletely LOT-transected rats. We concluded that the regenerated bulbar fibers were confined to the regions of the anterior olfactory cortices and that ectopic myelination of the regenerated LOT occurred only at a specific site near the rhinal sulcus.ArticleNEUROSCIENCE LETTERS. 537:35-39 (2013)journal articl

Effects of repeated crush injuries on motor functional recovery of the sciatic nerve

信州大学博士（医学）・学位論文・平成25年1月30日授与（乙第1153号）・伊坪 敏郎Objectives: The present study was conducted to examine whether repeated crush injuries have significant effects on motor functional recovery of peripheral nerves. Methods: Repeated crush injuries of the sciatic nerve were inflicted on adult rats at 1-week intervals, and functionality of the sciatic nerve was assessed by the static sciatic index each week for 8 weeks after the final injury. To determine the effects of repeated crush injuries on motor functional recovery of the sciatic nerve, tibialis anterior muscle fibers from single and triple crush injuries were examined, and fiber size and fiber reinnervation during the 2- to 4-week period after the final injury were measured. Results: Compared to single crush injuries, which completely recovered by post-injury week 4, double crush injuries resulted in retarded, but complete recovery by post-injury week 6, whereas triple crush injuries resulted in marked retardation in the regenerative process with incomplete recovery during week 8 of the experimental period. Muscle fiber size for rats with triple crush did not recover to normal range at post-injury week 4, despite its normal size for rats with single crush. The rate of reinnervation increased prominently between post-injury weeks 2 and 3 in both injuries, but the rate with triple crush was lower than that with single crush at post-injury week 3. Discussion: These results, which contradict those of a previous study that reported early functional recovery, indicate that repeated crush injuries inhibit motor functional recovery of the damaged sciatic nerve, as evidenced by delayed and incomplete regeneration, atrophied muscle fibers, and delayed reinnervation.ArticleNEUROLOGICAL RESEARCH. 34(9):908-914 (2012)journal articl

Transforming Growth Factor α Evokes Aromatase Expression in Gastric Parietal Cells during Rat Postnatal Development

Estrogen, well known as a female hormone, is synthesized primarily by ovarian aromatase. However, extra-glandular tissues also express aromatase and produce estrogen. It is noteworthy that aromatase in gastric parietal cells begins expression around 20 days after birth and continues secreting considerable amounts of estrogen into the portal vein throughout life, supplying it to the liver. Estrogen, which is secreted from the stomach, is speculated to play a monitoring role in blood triglyceride, and its importance is expected to increase. Nevertheless, the regulatory mechanisms of the aromatase expression remain unclear. This study investigated the influence of transforming growth factor α (TGFα) on gastric aromatase expression during postnatal development. The administration of TGFα (50 μg/kg BW) to male Wistar rats in the weaning period resulted in enhanced aromatase expression and increased phosphorylated ERK1+2 in the gastric mucosa. By contrast, administration of AG1478 (5 mg/kg BW), a protein tyrosine kinase inhibitor with high selectivity for the epidermal growth factor receptor and acting as an antagonist of TGFα, led to the suppression of aromatase expression. In fact, TGFα expression in the gastric fundic gland isthmus began around 20 days after birth in normal rats as did that of aromatase, which indicates that TGFα might induce the expression of aromatase in the parietal cells concomitantly