Morphometric Analyses and Aging Process of Nerve Fibers in the Human Spinal Posterior Funiculus

Okajimas Folia Anatomica Japonica

Tanaka

et al. 1997

Summary: The aim of the present study is to analyse nerve fibres of the human small splanchnic nerve in relation to the ageing process. The analysis was conducted with the use of a new staining method that makes it possible to discriminate various structures of the nervous tissue. An image-ansdysing digitiser, a microscope with a drawing tube and a personal computer for storing data and performing statistical analyses were employed in this study. We examined 30 human small splandmic nerves which were taken from cadaver specimens (20 males and 10 females) aged from 44 to 96 years. Our report may provide a first information concerning the ageing process of the human small splanchnic nerve. The results indicate that a decrease in transverse area and perimeter of myelinated axons in one of the important changes occurring in the human small splanchnic nerve with the ageing process.The autonomic nervous system affects the functions of all other systems and influences human behaviour. It is not surprising, therefore, that clinical manifestations of any illness are influenced by the autonomic nervous system which also affects interactions of individuals with their surroundings 1,6) As the nervous system is the most important one in the human body, changes with age in this particular system should be studied in detail. Up to now, several studies on the splanchnic nerve have been performed7.1°). However, to our knowledge, the age-related changes in the human small splanchnic nerve have not been studied yet. It is our purpose in the present study to bring age-related changes to light through analysis of numbers, transverse areas and perimeters of myelinated axons of the human small splanchnic nerve. Material and MethodsSmall sections of the splanchnic nerve situated near the diaphragm were removed from 30 human cadavers (20 males and 10 females) aged 44-96 years (average age: 70 years). The causes of death had no direct or indirect connection with the central or peripheral nervous system, so the small splanchnic nerves were considered to be normal. FixationThe fixation procedures consisted of two steps as follows: (1) Primary fixation: the material was kept in 3.7% formaldehyde for at least one week. (2) Secondary fixation: the material was immersed in a mixture of 5% potassium dichromate and 5% potassium chromate (1:4 in volume) for three weeks (two weeks at room temperature, and another week at 37°C). The volume of fixative was at least ten times the volume of the specimen. WashingAfter the fixation, tissue blocks fitted with a nylon-mesh bag or a plastic tissue-basket were washed in running water with a siphon-operated automatic pipette washer for several hours. Dehydration and celloidin embeddingThe tissue blocks were dehydrated with ethanol at 50%, 70%, 90%, 95% and pure, and then were embedded in celloidin. The shrinkage of nerve tissue sections during fixation and embedding amounted to approximately 10% in length.

Section: Discussionmentioning

confidence: 99%

Myelinated Nerve Fibre Analysis of the Human Small Splanchnic Nerve

Tang

Okajimas Folia Anatomica Japonica

Tanaka

et al. 1997

“…However, no evaluation of nerve fibers in the LCST is included in the literature regarding the cervical levels, apart from decrease with age of the number of axons in the posterior funiculus at the C6 level 7) . At the C5 level, we found similar results in the LCST, which contains axons innervating the anterior horn cells supplying the upper and lower extremities, compared to the data concerning the L1 level 1,2) .…”

Section: Discussionmentioning

confidence: 99%

Morphological evaluation of the human pyramidal tract: Gender and age differences

Souma¹,

Okajimas Folia Anat. Jpn.

et al. 2008

Self Cite

In the past, morphometric research on the nervous system had tended to focus on neuronal somata. Recently, however, research has started on the evaluation of the nervous pathways, especially of the nerve fibers [1][2][3][4][5][6][7][8] . Out of the reasons for this delay may be the lack of reliable methods for the staining of axons with minimum shrinkage. For example, conventional silver impregnation methods may result in extensive axonal shrinkage. It is therefore indispensable to adopt one of the discriminative staining methods developed recently for the evaluation of nerve fibers 8,9) , as it is very important to take into account the shrinkage ratio for the morphometric evaluation of human nerve tissue 8,9) . Such shrinkage should be avoided, or at least be as low as possible and have the narrowest range possible for the purpose. Although there are a few reports on the lateral corticospinal tract (LCST) at L1 level 1, 2) concerning aging or gender differences, no data can be found regarding the cervical levels. In the present report, we will describe the differnces due to gender and aging in nerve fiber axons in the LCST at the C5 level. Material and methodsSpinal cords, including the dura mater coverings and the proximal parts of the spinal nerves after checking the level of spinal nerve roots were removed from the cadavers of 43 human subjects consisting of 31 males (age ranging from 41 to 97 years) and 12 females (age ranging from 59 to 92 years), after injection of a 10% formalin (3.7-4.0% formaldehyde) solution through the femoral artery by a pulsation pump, with the jugular and femoral veins open for drainage of the blood. The subjects showed no evidence, either clinical or pathological, of suffering from diseases affecting the nervous system. We excluded cadavers with a past history of nervous diseases or pathological findings in the nervous system such as cerebrovascular disorders, intracranial tumors, infections, neurodegenerative conditions, etc. The spinal cords prepared for the study were therefore considered to be normal. After making the transverse sections, the selected segments were confirmed to be the fifth cervical segment according to Goto's criteria 10) . Blocks of the spinal cord segments were fixed in a two-step process according to the method given in the reference section 9) . For primary fixation, a 10% solution of formalin for general purposes was used. The blocks were first immersed in the solution over a week, and were then transferred, without washing, into the secondary fixative composed of 5% potassium dichromate and 5% potassium chromate (1:4 in volume) and kept at room temperature for two weeks, followed by an additional week at 37°C. After washing with running water using a pipet-washer with siphon mechanism Okajimas Folia Anat. Jpn., 85(3): 107-109, November, 2008 Morphological evaluation of the human pyramidal tract:Gender and age differences Summary: Using a preparation method composed of secondary chromic acid fixation, nitrocellulose embedding and Luxol fast blue-PAS...

“…A morphometric analysis was conducted to detect the aging of nerve fibers in the human spinal posterior funiculus 37 . Thirty‐eight spinal cords were taken from cadaver specimens (25 males and 13 females) aged from 41 to 97 years.…”

Section: Aging Processmentioning

confidence: 99%

Morphometric evaluations of the human nervous system

2006

Human Cell

Self Cite

It is very important to evaluate and accurately understand the various conditions of the human nervous system. In this review article, we introduce several morphometric reports that are proven to be accurate from the view point of various errors (range of tissue shrinkage ratios, microscopic multiple counting, artifacts of microscopic structures, etc.). We review the following aspects of the selected reports: methodology, developmental research, neuronal differences, gender differences, aging process and miscellaneous (nerve fibers, unmyelinated fibers, in relation to neuropathology, clinical image-analysis and immunohistochemistry).