Publications by authors named "Tetsuji Moriizumi"

44 Publications

Continuous and Connective Fibers of the Lateral Ankle Ligament Complex.

J Foot Ankle Surg 2020 Jul - Aug;59(4):679-684

Orthopedic Surgeon, Toyohashi Esaki Orthopedic Hospital, Aichi, Japan.

The lateral ankle ligament complex (LALC) is an intricate structure; therefore precise anatomic knowledge is required by the surgeon. However, the structural relationship of the LALC remains unclear. Here, the features of the posterior talofibular ligament (PTFL) and the relationship to the LALC at the distal fibula were clarified in a cadaver study. The lengths of most of the anterior and posterior parts, and the widths of the anterior-posterior and superior-inferior parts, were measured with a digital caliper. In addition, the relationship between the anterior talofibular ligament (ATFL) and PTFL inside of the capsule is described. The small fiber bundles of the PTFL were manually divided, and the footprint of each bundle at the fibula and talus was clarified. The relationship between the ATFL and CFL, outside of the capsule, was examined on axial slices at the inferior fibula. The lengths of the most anterior and most posterior parts of the PTFL were 9.8 ± 1.7 and 29.4 ± 1.9 mm, respectively. The widths of the anterior-posterior and superior-inferior parts were 10.0 ± 0.9 and 5.8 ± 1.1 mm, respectively. Approximately 83% of the fibers between the ATFL and PTFL were continuous. The anterior-inferior fibers of the PTFL were continuous with the inferior fibers of the ATFL inside of the capsule. The ATFL and CFL converged with connective tissue from outside of the capsule at the distal fibula. The results of this study should prove useful to further clarify the relationships of the LALC both inside and outside of the capsule at the distal fibula.
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http://dx.doi.org/10.1053/j.jfas.2019.09.025DOI Listing
June 2021

Hypoglossal nerve injury with long nerve resection leading to slow motoneuron death.

Neurosci Lett 2020 01 3;715:134668. Epub 2019 Dec 3.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan.

Crush injury to peripheral nerves in adult animals is considered not to trigger retrograde neuronal cell death; however, several studies reported neuronal cell death following severe injuries including nerve transection, resection, or avulsion. However, the rate of neuronal cell death varied among studies. In this study, we evaluated the outcomes of very severe nerve injury by long nerve resection in adult rats. Right hypoglossal (XII) nerve was exposed, and a 9-mm section was resected. At 4, 8, and 12 weeks after the resection, the number of XII neurons were counted in from the rostral to caudal sections. The number of XII neurons in the injured right side was reduced after the XII nerve resection compared with the uninjured left side. The mean rates of surviving neurons at 4, 8, and 12 weeks after the nerve resection were 83.5 %, 73.9 %, and 61.1 %, respectively, which were significantly lower than those of the control. The number of XII neurons after extensive XII nerve resection declined gradually over a relatively long time period, revealing that extensive nerve resection led to slow cell death of the injured neurons.
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http://dx.doi.org/10.1016/j.neulet.2019.134668DOI Listing
January 2020

Independent Attachment of Lateral Ankle Ligaments: Anterior Talofibular and Calcaneofibular Ligaments - A Cadaveric Study.

J Foot Ankle Surg 2019 Jul 23;58(4):717-722. Epub 2019 May 23.

Professor, Department of Anatomy, Shinshu University School of Medicine, Nagano, Japan.

Anatomic knowledge of lateral ligaments around the lateral malleolus is important for repair or reconstruction of ankle instability. The detailed structure of the connective fibers between the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) is unknown. To clarify the anatomic structure of ATFL and CFL and the connective fiber between the 2 ligaments, the lateral ligament was dissected in 60 ankles of formalin-fixed cadavers, and the distance was measured between bony landmarks and fibular attachment of ATFL and CFL using a digital caliper. All ankles had connective fibers between ATFL and CFL. The structure of connective fibers consisted of a thin fiber above the surface layer of ATFL and CFL; it comprised thin fibrils of the surface layer covering the lower part of ATFL and the front part of CFL. Both ATFL and CFL were independent fibers, and both attachments of the fibula were isolated. Single bands of ATFL were noted in 14 of 60 (23.3%) ankles, double bands that divided the superior and inferior bands were observed in 42 of 60 (70.0%) ankles, and multiple bands were observed in 4 of 60 (6.7%) ankles. A cord-like and a flat and fanning type of CFL was noted in 22 (36.7%) and 38 (63.3%) of the 60 ankles, respectively. Distances between ATFL/CFL and articular and inferior tips of the fibula were 4.3 ± 1.1 mm/7.6 ± 1.6 mm and 14.3 ± 1.9 mm/7.4 ± 1.7 mm, respectively (mean ± standard deviation). The results of this study suggest that knowledge of more anatomic structures of ATFL, CFL, and connective fiber will be beneficial for surgeons in the repair or reconstruction of the lateral ligament of the ankle.
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http://dx.doi.org/10.1053/j.jfas.2018.12.009DOI Listing
July 2019

Effects of various lengths of hypoglossal nerve resection on motoneuron survival.

J Clin Neurosci 2019 Feb 13;60:128-131. Epub 2018 Nov 13.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano, Japan. Electronic address:

We employed stereological analyses for whole quantification of hypoglossal (XII) motoneurons in adult rats that received varying degrees of resection of the XII nerve. Various lengths of nerve gaps (0.0-13.3 mm) were made at the main trunk of the unilateral XII nerve, and the total number of XII neurons on the injured and uninjured sides was counted 12 weeks after nerve resection. The stereologically estimated total number of XII neurons decreased after various lengths of nerve resection, and survival rates ranged from 34.4% to 87.1%. Statistically significant negative correlations were observed between increasing length of the resected nerve and decreasing XII neuron survival. It was concluded that the total number of XII neurons decreased after nerve resection and that survival rates of XII neurons were related to distances between resected nerve stamps.
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http://dx.doi.org/10.1016/j.jocn.2018.11.020DOI Listing
February 2019

Effects of repeated nerve injuries at different time intervals on functional recovery and nerve innervation.

J Clin Neurosci 2018 Feb 26;48:185-190. Epub 2017 Nov 26.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano, Japan. Electronic address:

Effects of repeated nerve injuries on functional recovery and nerve innervation were examined in rodents. Crush injuries of the sciatic nerve were inflicted on adult rats and repeated twice or thrice at different time intervals of 1, 2, 3, and 4 weeks. Motor function was assessed by the static sciatic index at 1, 7, 14, 21, 28, 35, 42, 49, and 56 days after the final crush. The rates of nerve innervation of the tibialis anterior muscle, a main muscle innervated by the common peroneal nerve, were evaluated by the quantification of βIII-tubulin-positive nerve terminals and α-bungarotoxin-positive acetylcholine receptors 21 and 56 days after the final crush of triple nerve injuries at 1-, 2-, 3-, and 4-week intervals. Compared with single nerve crush injury, delayed recovery of motor function was observed in repeated crush injuries. In addition, recoveries in the triple crush groups were slower than those in the double crush groups. The rates of reinnervation were lower in the triple crush groups than in the single crush groups, both at 21 days (single: 59.7%; triple: 54.1%-56.1%) and 56 days (single: 88.8%; triple: 72.5%-83.0%) after the final crush, except in the groups with 1-week (triple: 73.8%) and 2-week (triple: 70.5%) intervals at 21 days after the final crush. We concluded that the recovery of motor function was delayed according to the number of repetitions of crush injuries, and that the rates of nerve innervation were still low in the triple crush groups 8 weeks after the final crush.
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http://dx.doi.org/10.1016/j.jocn.2017.11.016DOI Listing
February 2018

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

Neurosci Lett 2017 Jul 3;653:215-219. Epub 2017 Jun 3.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan.

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.
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http://dx.doi.org/10.1016/j.neulet.2017.06.001DOI Listing
July 2017

Stereological assessment of the total number of hypoglossal neurons after repeated crush injuries to the hypoglossal nerve in adult rats.

Neurol Res 2017 Feb 4;39(2):183-188. Epub 2017 Jan 4.

a Department of Anatomy , Shinshu University School of Medicine , Matsumoto , Japan.

Objective: Retrograde neuronal cell death does not occur in mature motoneurons following the axonal injury of peripheral nerves. However, a previous study suggested that retrograde neuronal cell death does occur in adult rats after the creation of double lesions on the hypoglossal (XII) nerve based on a substantial decrease in the number of XII neurons. Using stereological methods, we examined neuronal apoptosis in XII neurons and the total number of XII neurons following repeated crush injuries to the XII nerve.

Methods: The right XII nerve of adult rats was crushed three times at one-week intervals with a brain aneurysm clip. At 4 weeks after the final crush, the total numbers of XII neurons on the injured right and uninjured left sides were estimated stereologically.

Results: After repeated crush injuries, no apoptosis was evident in XII neurons as indicated by immunostaining for cleaved caspase-3. Moreover, immunohistochemistry for the vesicular acetylcholine transporter revealed axonal elongation in the tongue 4 weeks after repeated crush injuries. At 4 weeks, the total numbers of XII neurons were 7800 ± 290 on the injured right side and 8000 ± 230 on the uninjured left side, and no significant difference was evident between the injured and uninjured sides.

Conclusion: Neuronal cell death does not occur in XII neurons and the total number of XII neurons does not decrease after repeated crush injuries of the XII nerve in adult rats.
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http://dx.doi.org/10.1080/01616412.2016.1275461DOI Listing
February 2017

Morphological analysis of regenerated bulbar fibers in relation to neonatal olfaction.

Brain Res Bull 2016 10 26;127:66-73. Epub 2016 Aug 26.

Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.

It was revealed that regeneration of the lateral olfactory tract (LOT) occurred in developing rats and the regenerated olfactory system was functional 4 weeks after transection. The aim of this study was to determine the earliest onset of functional recovery in LOT-injured rats and to quantify regenerated nerve components with functional correlation. Neonatal rats on postnatal day (P) 2 were subjected to unilateral transection of the left LOT and underwent unilateral removal of the right olfactory bulb on P11. Functional recovery of the tract injury was assessed by the suckling capability, which can be achieved by olfaction. Suckling capability was observed on P12 in most neonatally LOT-transected pups. Rat pups were subjected to unilateral transection of the left LOT on P2, and received injections of biotinylated dextran amine (BDA) into the bilateral olfactory bulb on P5 to quantify normal and regenerated nerve components in the olfactory cortices at the level of the olfactory tubercle. BDA(+) areas and density indices of the olfactory cortices in the neonatally LOT-transected P12 pups were 11.05×10μm and 0.35 on the normal right side and 4.34×10μm and 0.21 on the transected left side. We concluded that functional recovery of the LOT-transected neonatal rats occurred as early as 10days after tract transection and that areas and densities of regenerated nerve components essential for functional recovery were approximately 40% and 60% of the age-matched normal values in the olfactory cortices at the level of the olfactory tubercle.
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http://dx.doi.org/10.1016/j.brainresbull.2016.08.015DOI Listing
October 2016

Elastic modulus of the femoral trochanteric region measured by scanning acoustic microscopy in elderly women.

J Med Ultrason (2001) 2015 Jul 25;42(3):303-13. Epub 2015 Jan 25.

Department of Orthopaedic Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.

Purpose: We have devised a method that can obtain continuous detailed distributions of the elastic modulus along the measurement line in a non-decalcified specimen of human bone tissue. The aim of this study was to determine whether local variations exist in the distribution of mechanical properties within the trochanteric region of the femur of elderly females using a newly developed form of scanning acoustic microscopy (SAM) technology.

Methods: Human proximal femurs were harvested from seven female cadavers aged between 67 and 88 years at death. Using data collected with SAM, the elastic modulus of cortical and trabecular bone tissue of the lateral and medial trochanter was calculated and statistically analyzed.

Results: The longitudinal and transverse elastic moduli in cortical bone tissue of the lateral trochanter were found to be significantly lower than those of the medial trochanter in all specimens from individuals over age 70 (p < 0.05). Compared to that of the distal region, the longitudinal and transverse elastic moduli of trabecular bone tissue of the proximal region of the lateral trochanter were significantly lower in all specimens from individuals over age 80 (p < 0.05).

Conclusion: Our new method allows obtaining detailed distributions of the elastic modulus of bone tissue.
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http://dx.doi.org/10.1007/s10396-014-0608-yDOI Listing
July 2015

Effect of graded nerve pressure injuries on motor function.

J Neurosurg 2015 Jun 6;122(6):1438-43. Epub 2015 Mar 6.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan.

Object: The purpose of this study was to determine the minimum amount of nerve fibers required to maintain normal motor function after nerve injury in rats.

Methods: The authors first confirmed that a common peroneal nerve injury caused more aggravating effects on lower limb motor function than tibial nerve injury, as assessed by the static sciatic index (SSI). Thereafter, rats were subjected to varying degrees of crush injury to the common peroneal nerve. At 48 hours after the injury, motor function was assessed using the SSI and slope-walking ability (with slope angles of 30° and 45°). The tibialis anterior muscle, a main muscle innervated by the common peroneal nerve, was removed. Muscle sections were co-labeled with neuronal class III β-tubulin polyclonal antibody to identify the presence of axons and Alexa Fluor 488-conjugated α-bungarotoxin to identify the presence of motor endplates.

Results: The evaluation of neuromuscular innervation showed a correlation between SSI scores and ratios of residual axons (rs = 0.68, p < 0.01), and there was a statistically significant difference between slope-walking ability and ratios of residual axons (p < 0.01). Moreover, the ratios of residual axons in the nerve-crushed rats with normal motor function (SSI above -20) ranged from 36.5% to 88.7%, and those ratios in the success group with slope-walking angles of 30° and 45° ranged from 14.7% to 88.7% and from 39.8% to 88.7%, respectively.

Conclusions: In this study of rodents, less than half of the motor axons were sufficient to maintain normal motor function of the lower limb.
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http://dx.doi.org/10.3171/2014.9.JNS141451DOI Listing
June 2015

Two specific tongue regions receive bilateral hypoglossal innervation: a study in neonatal rat pups.

Arch Oral Biol 2015 Mar 11;60(3):432-8. Epub 2014 Dec 11.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan.

Objective: The purpose of this study was to investigate the functional role of bilateral hypoglossal (XII) nerve innervation of the tongue.

Materials And Methods: The possibility of bilateral innervation of XII nerve in the tongue was examined using postmortem fibre tracing in normal neonatal rats. In addition, immunohistochemical testing for synaptophysin or vesicular acetylcholine transporter (VAChT) was carried out in unilaterally XII nerve-resected neonatal rats.

Results: Postmortem fibre tracing revealed constant distribution of the nerve fibres extending across the midline and existence of bilateral innervated area in the rostroventral and caudodorsal regions of the tongue. Synaptophysin-positive and VAChT-positive nerve terminals were also distributed continuously from the XII nerve-intact to the nerve-resected side across the midline of the tongue. The contralaterally projecting VAChT-positive nerve terminals were more numerous in suckling P2 rats (6.6 ± 0.5/section) than those in non-suckling P2 rats (4.9 ± 0.3/section) 24 h after nerve resection. Furthermore, the contralaterally projecting VAChT-positive nerve terminals were more numerous in P7 rats with nerve resection on P1 (6.3 ± 0.2/section) than those in P7 rats with nerve resection on P6 (3.1 ± 0.8/section).

Conclusion: We concluded that neonatal rats have two specific tongue regions receiving bilateral XII innervation, which allowed suckling in unilaterally XII nerve-resected neonatal rats.
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http://dx.doi.org/10.1016/j.archoralbio.2014.12.002DOI Listing
March 2015

Stereological estimation of olfactory receptor neurons in rats.

Chem Senses 2015 Feb 23;40(2):89-95. Epub 2014 Dec 23.

Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.

The total number of olfactory receptor neurons (ORNs) in the rat main olfactory epithelium (MOE) was estimated using stereological sampling. Skulls and noses of newborn (postnatal day 0), young adult (8 weeks), and adult (6 months) rats were decalcified, embedded in paraffin, cut into 10-μm thick sections serially at 100-μm intervals, and processed for immunohistochemistry for olfactory marker protein (OMP), a specific marker of mature ORNs with fiber connections to the olfactory bulb. The number of OMP (+) receptor neurons was measured using an optical fractionator with stereological software (Stereoinvestigator). The total number of OMP (+) receptor neurons in the unilateral MOE was 0.47 × 10(6) in newborns and 21 × 10(6) in young adults and adults. Our previous study showed that the corresponding unilateral total number of neurons was 5.2 × 10(6) in young adult mice. Accordingly, we concluded that rats had 4 times more OMP (+) receptor neurons than mice at the adult stage and that the number of these neurons increased approximately 45 times between birth and maturity.
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http://dx.doi.org/10.1093/chemse/bju062DOI Listing
February 2015

Inhibitory role of the serotonergic system on estrogen receptor α expression in the female rat hypothalamus.

Neurosci Lett 2014 Nov 2;583:194-8. Epub 2014 Oct 2.

Laboratory of Neuroendocrinology, Department of Human Behavior and Environment Sciences, School of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192, Japan. Electronic address:

The role of the serotonergic system in regulating the expression of estrogen receptor (ER) α in the hypothalamus was investigated in ovariectomized rats by injecting a serotonin synthesis inhibitor, parachlorophenylalanine (PCPA), or by destroying the dorsal raphe nucleus (DR). The number of ERα-immunoreactive (ir) cells was counted in the anteroventral periventricular nucleus in the preoptic area (AVPV), ventrolateral ventromedial hypothalamic nucleus (vlVMN), and arcuate nucleus (ARCN). Seven days after ovariectomy, 100mg/kg PCPA or saline was injected daily for 4 days. Alternatively, radiofrequency lesioning of the DR (DRL) or sham lesions were made on the same time of ovariectomy. One-day after the last injection of PCPA or 7 days after brain surgery, the brain was fixed for immunostaining of ERα and the number of ERα-ir cell were counted in the nuclei of interest. The mean number of ERα-ir cells/mm(3) (density) in the AVPV of the PCPA or DRL groups was statistically higher than that in the saline or sham group. In the vlVMN and ARCN of the PCPA or DRL groups, the mean density of ERα-ir cells was comparable to the saline or sham groups. These results suggest that the serotonergic system of the DR plays an inhibitory role on the expression of ERα in the AVPV, but not in the vlVMN and ARCN.
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http://dx.doi.org/10.1016/j.neulet.2014.09.043DOI Listing
November 2014

Effect of synovial transthyretin amyloid deposition on preoperative symptoms and postoperative recovery of median nerve function among patients with idiopathic carpal tunnel syndrome.

J Orthop Sci 2014 Nov 22;19(6):913-9. Epub 2014 Aug 22.

Department of Orthopaedic Surgery, Shinshu University School of Medicine, Asahi 3-1-1, Matsumoto, 390-8621, Japan,

Background: The clinical characteristics of wild-type transthyretin amyloid deposition among patients with carpal tunnel syndrome (CTS) have not been well investigated.

Methods: One-hundred and seven patients with idiopathic CTS who underwent carpal tunnel release were enrolled. They underwent physical examination of the hand, nerve-conduction study, and magnetic resonance imaging (MRI) study of the wrist, and completed a patient-oriented questionnaire. The tests, except for MRI, were repeated 1, 3, and 6 months postoperatively. Synovial tissue was obtained during surgery and analyzed by Congo red and immunohistochemical staining. Ordinal logistic regression analysis was used to evaluate the significance of different clinical and subjective findings between patients with and without amyloid deposition. Postoperative improvements were also compared.

Results: Wild-type transthyretin amyloid deposition was observed for 38 patients. Greater symptom severity and 2-point discrimination scores, and larger cross-sectional areas of the carpal tunnel, were significantly correlated with a larger amount of preoperative amyloid deposition. However, the presence and amount of preoperative amyloid deposition did not affect postoperative improvements in physical findings and nerve-conduction studies.

Conclusions: Although transthyretin amyloid deposition can worsen CTS symptoms, postoperative improvements were similar for patients with and without this deposition.
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http://dx.doi.org/10.1007/s00776-014-0635-yDOI Listing
November 2014

Correlation between motor function and axonal morphology in neonatally sciatic nerve-injured rats.

Anat Sci Int 2015 Mar 26;90(2):97-103. Epub 2014 Apr 26.

Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.

The present study was conducted to investigate the correlation between motor function and axonal morphology in neonatally sciatic nerve-injured rats. The left sciatic nerve of newborn rats was transected or crushed, and functionality of the sciatic nerve was assessed by the static sciatic index after 8 weeks. After functional assessment, the common peroneal nerves in the control, nerve-transected, and nerve-crushed rats were removed and prepared for morphometric examinations. The cross-sectional area of the nerve, total number of myelinated axons, and size of each myelinated axon were analyzed for each group. The control rats showed normal motor function, whereas the nerve-transected rats showed severe motor dysfunction. The cross-sectional area of the nerve and total number of myelinated axons were reduced after nerve transection. Moreover, the percentage per size class of myelinated axons was almost uniform in the control rats, while the distribution was shifted to the left in the nerve-transected rats. Furthermore, no large myelinated axons were observed in the nerve-transected rats. The nerve-crushed rats showed various gait functions with various distribution patterns of axonal size, and the rats were divided into two groups with and without uninjured residual large axons. The results showed that the importance of regenerated medium-sized axons in cases without large axons and of residual large axons in cases with large axons in motor function. It was revealed that motor function was related closely to axonal size in neonatally nerve-injured rats.
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http://dx.doi.org/10.1007/s12565-014-0236-zDOI Listing
March 2015

Bony Landmarks of the Anterior Cruciate Ligament Tibial Footprint: A Detailed Analysis Comparing 3-Dimensional Computed Tomography Images to Visual and Histological Evaluations.

Am J Sports Med 2014 Jun 18;42(6):1433-40. Epub 2014 Apr 18.

Department of Applied Physical Therapy, Shinshu University School of Medicine, Matsumoto, Japan

Background: Although the importance of tibial tunnel position for achieving stability after anterior cruciate ligament (ACL) reconstruction was recently recognized, there are fewer detailed reports of the anatomy of the tibial topographic footprint compared with the femoral side.

Hypothesis: The ACL tibial footprint has a relationship to bony prominences and surrounding bony landmarks.

Study Design: Descriptive laboratory study.

Methods: This study consisted of 2 anatomic procedures for the identification of bony prominences that correspond to the ACL tibial footprint and 3 surrounding landmarks: the anterior ridge, lateral groove, and intertubercular fossa. In the first procedure, after computed tomography (CT) was performed on 12 paired, embalmed cadaveric knees, 12 knees were visually observed, while their contralateral knees were histologically observed. Comparisons were made between macroscopic and microscopic findings and 3-dimensional (3D) CT images of these bony landmarks. In the second procedure, the shape of the bony prominence and incidence of their bony landmarks were evaluated from the preoperative CT data of 60 knee joints.

Results: In the first procedure, we were able to confirm a bony prominence and all 3 surrounding landmarks by CT in all cases. Visual evaluation confirmed a small bony eminence at the anterior boundary of the ACL. The lateral groove was not confirmed macroscopically. The ACL was not attached to the lateral intercondylar tubercle, ACL tibial ridge, and intertubercular space at the posterior boundary. Histological evaluation confirmed that the anterior ridge and lateral groove were positioned at the anterior and lateral boundaries, respectively. There was no ligament tissue on the intercondylar space corresponding to the intercondylar fossa. In the second investigation, the bony prominence showed 2 morphological patterns: an oval type (58.3%) and a triangular type (41.6%). The 3 bony landmarks, including the anterior ridge, lateral groove, and intertubercular fossa, existed in 96.6%, 100.0%, and 96.6% of the cases, respectively.

Conclusion: There is a bony prominence corresponding to the ACL footprint and bony landmarks on the anterior, posterior, and lateral boundaries.

Clinical Relevance: The study results may help create an accurate and reproducible tunnel, which is essential for successful ACL reconstruction surgery.
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http://dx.doi.org/10.1177/0363546514528789DOI Listing
June 2014

Quantitative analysis of survival of hypoglossal neurons in neonatally nerve-injured rats: Correlation with milk intake.

Arch Oral Biol 2014 Jun 28;59(6):616-20. Epub 2014 Feb 28.

Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.

Introduction: Tongue movement innervated by the hypoglossal (XII) nerve is essential for the survival of neonatal rats. The pups with bilateral XII nerve resection failed to suckle milk and did not survive, and the pups with unilateral XII nerve resection showed disturbed suckling capability and lower survival rates. The present study was performed to investigate the relation between neuronal population and milk intake of developing rats that had received various degrees of crush injuries to the unilateral XII nerve during the neonatal period.

Methods: The right XII nerve of postnatal day 1 (P1) pups was crushed and milk intake was estimated at 3 days and 6 days after the nerve injury. As nerve injury at the neonatal stage results in death of axotomized neurons, varying degrees of crushing was estimated by the number of survived motor neurons.

Results: In nerve-crushed rats, the populations of XII motor neurons and amounts of milk intake were reduced in a varied manner. Statistically significant positive correlations were observed between increasing XII neuron survival and increasing milk intake at 3 (r=0.62) and 6 (r=0.71) days after the nerve injury.

Conclusion: The results indicate that there is a strong relationship between the number of XII motor neurons and the amount of milk intake in neonatally XII nerve-injured rats.
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http://dx.doi.org/10.1016/j.archoralbio.2014.02.012DOI Listing
June 2014

Postnatal changes in the number of serotonin-immunoreactive cells in midbrain raphe nuclei of male rats.

Anat Sci Int 2014 Sep 30;89(4):199-206. Epub 2013 Nov 30.

Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.

To clarify the developmental changes in serotonergic neurons in the subdivisions of the dorsal (DR) and median raphe (MR) nuclei before puberty, the extent of the nuclei and the number of serotonin (5-HT) immunoreactive (ir) cells were measured in 5-, 15-, and 30-day-old rats and 8-week-old (adult) castrated male rats. The brains were fixed and 50 μm frozen sections prepared. After immunostaining for 5-HT, the number of 5-HT-ir cells in a 0.2 × 0.2 mm frame in the dorsal, ventral and lateral subdivisions of the DR (dDR, vDR and lDR, respectively) and MR were counted. Total numbers of 5-HT-ir cells counted in the frame of three sections in each rat were expressed as the number of cells per cubic millimeter (density). The results indicated that the densities of 5-HT-ir cells in the MR were almost the same in all age groups. On the other hand, among the subdivisions of the DR, the mean density of 5-HT-ir cells in 15-day-old rats was higher than that in the 5-day-old group in the lDR only. The area of the three sections of the DR and of the MR was also measured. The area of the DR in 15-day-old rats was found to be twice that in the 5-day-old rats, and differed from the area in 30-day-old rats and adults. There were no differences among the age groups in the areas of the MR. The results indicate that the expression of 5-HT in the lDR and extent of the DR increased to adult levels from days 5 to 15 after birth. In the dDR, vDR and MR, expression of 5-HT at postnatal day 5 was at adult levels already.
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http://dx.doi.org/10.1007/s12565-013-0217-7DOI Listing
September 2014

Regenerative capacity of bulbar projection neurons during development: a quantitative neuronal analysis with functional correlation.

Chem Senses 2014 Jan 11;39(1):47-56. Epub 2013 Nov 11.

Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.

Critical periods and degrees of regeneration in injured olfactory bulbar projection neurons (mitral cells) were examined in adult rats whose lateral olfactory tracts (LOTs) were transected at different postnatal (P) days. After the LOTs were transected at P7, P10, and P14, a retrograde fluorescent tracer, Fluoro-Gold (FG), was injected into the posterior olfactory cortex (the olfactory tubercle and the piriform cortex), a target brain region of mitral cells, 5 weeks after the transection. FG (+) mitral cells were observed in P7 LOT-transected bulbs and some of P10 LOT-transected bulbs but not in P14 LOT-transected bulbs. Neuron numbers of regenerated FG (+) mitral cells in P2 LOT-transected adult rats decreased to approximately 70% of the normal values (actually counted number: 804±46; stereologically estimated number: 49 700±4300), and 100% of these rats were demonstrated to exhibit olfactory discriminative ability in our previous study. Meanwhile, the numbers in P7 LOT-transected adult rats further decreased to approximately 40% of the normal values, and 78% of these rats showed olfactory discriminative ability. We conclude that the critical periods of spontaneous regeneration of the LOT are between P0 and P10 and that the proportions of regenerated mitral cells decreased as rats became older.
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http://dx.doi.org/10.1093/chemse/bjt053DOI Listing
January 2014

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

Neurosci Lett 2013 Mar 24;537:35-9. Epub 2013 Jan 24.

Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.

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.
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http://dx.doi.org/10.1016/j.neulet.2013.01.016DOI Listing
March 2013

Cell bodies of the trigeminal proprioceptive neurons that transmit reflex contraction of the levator muscle are located in the mesencephalic trigeminal nucleus in rats.

J Plast Surg Hand Surg 2012 Dec;46(6):383-8

Department of Plastic and Reconstructive Surgery, Shinshu University School of Medicine, Matsumoto, Japan.

Since the levator and frontalis muscles lack interior muscle spindles despite being antigravity mixed muscles to involuntarily sustain eyelid opening and eyebrow lifting, this study has proposed a hypothetical mechanism to compensate for this anatomical defect. The voluntary contraction of fast-twitch fibres of the levator muscle stretches the mechanoreceptors in Müller's muscle to evoke proprioception, which continuously induces reflex contraction of slow-twitch fibres of the levator and frontalis muscles. This study confirmed the presence of cell bodies of the trigeminal proprioceptive neurons that transmit reflex contraction of the levator and frontalis muscles. After confirming that severing the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle induced ipsilateral eyelid ptosis, Fluorogold was applied as a tracer to the proximal stump of the trigeminal proprioceptive nerve in rats. Fluorogold labelled the cell bodies of the trigeminal proprioceptive neurons, not in any regions of the rat brain including the trigeminal ganglion, but in the ipsilateral mesencephalic trigeminal nucleus neighbouring the locus ceruleus. Some Fluorogold particles accumulated in the area of the locus ceruleus. The trigeminal proprioceptive neurons could be considered centrally displaced ganglion cells to transmit afferent signal from the mechanoreceptors in Müller's muscle to the mesencephalon, where they may be able to make excitatory synaptic connections with both the oculomotor neurons and the frontalis muscle motoneurons for the involuntary coordination of the eyelid and eyebrow activities, and potentially to the locus ceruleus.
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http://dx.doi.org/10.3109/2000656X.2012.722094DOI Listing
December 2012

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

Neurol Res 2012 Nov 22;34(9):908-14. Epub 2012 Aug 22.

Shinshu University School of Medicine, Matsumoto, Japan.

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.
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http://dx.doi.org/10.1179/1743132812Y.0000000089DOI Listing
November 2012

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

Neurosci Res 2012 May 21;73(1):17-23. Epub 2012 Feb 21.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.

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 2.4mm (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 4.2mm (n=10). From these data, we concluded that the site of the LOT critical for olfactory function is located approximately 2.5mm from the middle cerebral artery.
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http://dx.doi.org/10.1016/j.neures.2012.02.006DOI Listing
May 2012

A Contractile Network of Interstitial Cells of Cajal in the Supratarsal Mueller's Smooth Muscle Fibers With Sparse Sympathetic Innervation.

Eplasty 2012 15;12:e13. Epub 2012 Feb 15.

Background: We previously reported that the supratarsal Mueller's muscle is innervated by both sympathetic efferent fibers and trigeminal proprioceptive afferent fibers, which function as mechanoreceptors-inducing reflexive contractions of both the levator and frontalis muscles. Controversy still persists regarding the role of the mechanoreceptors in Mueller's muscle; therefore, we clinically and histologically investigated Mueller's muscle.

Methods: We evaluated the role of phenylephrine administration into the upper fornix in contraction of Mueller's smooth muscle fibers and how intraoperative stretching of Mueller's muscle alters the degree of eyelid retraction in 20 patients with aponeurotic blepharoptosis. In addition, we stained Mueller's muscle in 7 cadavers with antibodies against α-smooth muscle actin, S100, tyrosine hydroxylase, c-kit, and connexin 43.

Results: Maximal eyelid retraction occurred approximately 3.8 minutes after administration of phenylephrine and prolonged eyelid retraction for at least 20 minutes after administration. Intraoperative stretching of Mueller's muscle increased eyelid retraction due to its reflexive contraction. The tyrosine hydroxylase antibody sparsely stained postganglionic sympathetic nerve fibers, whereas the S100 and c-kit antibodies densely stained the interstitial cells of Cajal (ICCs) among Mueller's smooth muscle fibers. A connexin 43 antibody failed to stain Mueller's muscle.

Conclusions: A contractile network of ICCs may mediate neurotransmission within Mueller's multiunit smooth muscle fibers that are sparsely innervated by postganglionic sympathetic fibers. Interstitial cells of Cajal may also serve as mechanoreceptors that reflexively contract Mueller's smooth muscle fibers, forming intimate associations with intramuscular trigeminal proprioceptive fibers to induce reflexive contraction of the levator and frontalis muscles.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3281372PMC
August 2012

Decrease in the density of t-tubular L-type Ca2+ channel currents in failing ventricular myocytes.

Am J Physiol Heart Circ Physiol 2011 Mar 30;300(3):H978-88. Epub 2010 Dec 30.

Department of Anatomy and Molecular Pharmacology, Shinshu University School of Medicine, Nagano, Japan.

In some forms of cardiac hypertrophy and failure, the gain of Ca(2+)-induced Ca(2+) release [CICR; i.e., the amount of Ca(2+) released from the sarcoplasmic reticulum normalized to Ca(2+) influx through L-type Ca(2+) channels (LTCCs)] decreases despite the normal whole cell LTCC current density, ryanodine receptor number, and sarcoplasmic reticulum Ca(2+) content. This decrease in CICR gain has been proposed to arise from a change in dyad architecture or derangement of the t-tubular (TT) structure. However, the activity of surface sarcolemmal LTCCs has been reported to increase despite the unaltered whole cell LTCC current density in failing human ventricular myocytes, indicating that the "decreased CICR gain" may reflect a decrease in the TT LTCC current density in heart failure. Thus, we analyzed LTCC currents of failing ventricular myocytes of mice chronically treated with isoproterenol (Iso). Although Iso-treated mice exhibited intact t-tubules and normal LTCC subunit expression, acute occlusion of t-tubules of isolated ventricular myocytes with osmotic shock (detubulation) revealed that the TT LTCC current density was halved in Iso-treated versus control myocytes. Pharmacological analysis indicated that kinases other than PKA or Ca(2+)/calmodulin-dependent protein kinase II insufficiently activated, whereas protein phosphatase 1/2A excessively suppressed, TT LTCCs in Iso-treated versus control myocytes. These results indicate that excessive β-adrenergic stimulation causes the decrease in TT LTCC current density by altering the regulation of TT LTCCs by protein kinases and phosphatases in heart failure. This phenomenon might underlie the decreased CICR gain in heart failure.
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http://dx.doi.org/10.1152/ajpheart.00508.2010DOI Listing
March 2011

Re-evaluation of spontaneous regeneration of the lateral olfactory tract.

Neurosci Res 2010 Sep 27;68(1):15-21. Epub 2010 May 27.

Department of Neurosurgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.

Spontaneous regeneration of the lateral olfactory tract (LOT) was re-evaluated in newborn rats using a fluorescent retrograde neuronal tracer as objective indicators of complete LOT transection. Complete LOT transection was evidenced by the loss of the white myelinated band characteristic for adult LOT and the total lack of retrograde neuronal labeling of mitral cells by Fast Blue that was injected during LOT transection. In completely LOT-transected young adult rats, mitral cells were retrogradely labeled consistently only by Fluoro-Gold that was injected into the olfactory cortex at the adult stage. Moreover, an anterograde neuronal tracer, biotinylated dextran amine (BDA), was demonstrated to pass from the neonatally LOT-transected bulb, through the transected retrobulbar site, towards the olfactory cortex, far caudally at a level near the optic chiasm. The regenerated structures lacked immunoreactivity for myelin basic protein and electron-dense myelinated axon bundles, and were also characterized by the thinness of the BDA+ terminal zone within the olfactory cortex and the lack of its caudal extension. Young adult rats subjected to unilateral bulbectomy contralateral to the neonatally LOT-transected side showed perfect ability to discriminate cycloheximide solution by olfaction. From these findings, we conclude that the spontaneously regenerated olfactory system is functional despite structural incompleteness.
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http://dx.doi.org/10.1016/j.neures.2010.05.004DOI Listing
September 2010

Determination of functionally essential neuronal population of the olfactory epithelium for nipple search and subsequent suckling behavior in newborn rats.

Brain Res 2009 Jun 22;1276:50-7. Epub 2009 Apr 22.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan.

Neuronal population of the olfactory epithelium required for nipple search and subsequent suckling behavior was examined in newborn rats. After unilateral ablation of the olfactory bulb, different concentrations of ZnSO(4) were contralaterally injected into the nasal cavity to produce varying degrees of neuronal degeneration in the olfactory epithelium. The ZnSO(4)-treatment resulted in two populations of pups. One exhibited suckling while the other did not, and intact olfactory receptor neurons were quantified immunohistochemically using an antibody for olfactory marker protein (OMP), a marker protein for olfactory receptor neurons. The total numbers of the OMP (+) cells in the ZnSO(4)-treated pups with suckling capability ranged between 2457 and 4615, whereas those in the ZnSO(4)-treated pups without suckling capability ranged between 112 and 2398. With the mean value (4969) of the total numbers of the OMP (+) cells of the normal/control pups assumed to represent 100%, the total numbers of the OMP (+) cells accounted for 49-93% in the suckling (+) group and 2-48% in the suckling (-) group. From these findings, we conclude that approximately 50% of neuronal population of the olfactory epithelium is a critical value to distinguish between the two groups with and without suckling capability in the unilateral olfactory system of newborn rats.
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http://dx.doi.org/10.1016/j.brainres.2009.04.032DOI Listing
June 2009

Refined distribution of myelinated trigeminal proprioceptive nerve fibres in Mueller's muscle as the mechanoreceptors to induce involuntary reflexive contraction of the levator and frontalis muscles.

J Plast Reconstr Aesthet Surg 2009 Nov 19;62(11):1403-10. Epub 2008 Oct 19.

Department of Plastic and Reconstructive Surgery, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan.

Stretching of mechanoreceptors in Mueller's muscle induces reflexive contraction of not only the levator muscle but also the frontalis muscle as two different eyelid-opening muscles. Previously, we reported that fine neural myelinated structures, acting as mechanoreceptors, were found in the proximal Mueller's muscle. Since there is a risk of misunderstanding that the middle and distal Mueller's muscle does not contain mechanoreceptors and can be invalidated or resected, the accurate distribution of myelinated trigeminal proprioceptive nerve fibres as mechanoreceptors in Mueller's muscle was refined horizontally in this study. We explored 10 whole Mueller's muscles between the levator muscle and the tarsus of the upper eyelids obtained from five Japanese cadavers. The specimens were serially sliced along the horizontal plane and stained with HE, S-100 protein to determine the presence of Schwann cells, and smooth muscle actin antibody to determine the presence of Mueller's smooth muscle fibres. Although all myelinated nerve fibres in the intermuscular connective tissues among the sympathetically innervated Mueller's multi-unit smooth muscle fibres may not correspond to the proprioceptive nerve fibres, the nerve bundles consisting of multiple myelinated nerve fibres were well distributed in the proximal Mueller's muscle, and single myelinated nerve fibres were well distributed in the middle and distal Mueller's muscle. We believe that the mechanoreceptors in Mueller's muscle consist of myelinated proprioceptive nerve fibres with nerve endings possibly attached to collagen fibres in the intermuscular connective tissues present among Mueller's smooth muscle fibres. As the myelinated nerve fibres innervate the middle and distal Mueller's muscle to a greater extent than those in the proximal Mueller's muscle, the former may be more important as mechanoreceptors than the latter and should not be invalidated or excised during surgery for treatment of blepharoptosis to prevent reduction of reflexive contraction of the levator and frontalis muscles.
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http://dx.doi.org/10.1016/j.bjps.2008.06.046DOI Listing
November 2009

Tyrosine hydroxylase-immunoreactive fibers in the human vagus nerve.

J Clin Neurosci 2008 Sep 9;15(9):1023-6. Epub 2008 Jul 9.

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan.

Sympathetic catecholaminergic fibers in the vagus nerve were immunohistochemically examined in formalin-fixed human cadavers using an antibody against the noradrenalin-synthetic enzyme tyrosine hydroxylase (TH). TH-positive fibers were extensively distributed in the vagal nerve components, including the superior and inferior ganglia, the main trunk and the branches (superior and recurrent laryngeal, superior and inferior cardiac, and pulmonary branches). The inferior ganglion and its continuous cervical main trunk contained numerous TH-positive fibers with focal or diffuse distribution patterns in each nerve bundle. From these findings, we conclude that sympathetic fibers are consistently included in the human vagus nerve, a main source of parasympathetic preganglionic fibers to the cervical, thoracic and abdominal visceral organs.
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http://dx.doi.org/10.1016/j.jocn.2007.08.032DOI Listing
September 2008

Neural plasticity of neonatal hypoglossal nerve for effective suckling.

J Neurosci Res 2007 Aug;85(11):2518-26

Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.

The adaptive movement of the tongue after unilateral lesion of the hypoglossal (XII) nerve during the early postnatal days is essential for recovery of milk intake. The present study investigated the basic mechanisms underlying such adaptation, focusing on the neural plasticity that allows effective suckling. After resection of the ipsilateral XII nerve on P1, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlolate (DiI), a postmortem neuronal tracer, was applied to the contralateral uninjured XII nerve on P4 and P7. DiI-labeled fibers were traced successfully within the tongue and showed gradually increased extension over the XII nerve-injured side in the central core portion of the denervated tongue between P4 and P7. Systematic neuroanatomic experiments showed that contralateral axonal sprouting occurred as early as 1 day after nerve injury (P2), and that such axonal sprouting occurred exclusively from the medial branch of the XII nerve responsible for tongue protrusion, an essential movement for suckling. These findings provide direct evidence of functional neural plasticity that allows effective suckling in XII nerve-injured newborns with suckling disturbance.
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http://dx.doi.org/10.1002/jnr.21383DOI Listing
August 2007
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