Hepatitis E Virus in Cambodia: Prevalence among the General Population and Complete Genome Sequence of Genotype 4.

Hepatitis E virus (HEV) is a growing public health problem in many countries. In this study, we investigated HEV seroprevalence among the general population in the Siem Reap province, Cambodia, and performed HEV genetic analysis with the aim to develop an HEV prevention strategy. This seroepidemiological cross-sectional study conducted from 2010 to 2014 included 868 participants from four different locations in Siem Reap province, Cambodia.

Seroprevalence, genotypic distribution and potential risk factors of hepatitis B and C virus infections among adults in Siem Reap, Cambodia.

Aim: We investigated hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among adults in Siem Reap, Cambodia, to consider the prevention strategy in cooperation with the Ministry of Health in Cambodia.

Methods: Serological tests for determining HBV and HCV infections and questionnaires were performed from 2010 to 2012 among the general population in the province of Siem Reap. Multivariate logistic regression analysis was conducted to clarify the factors related to HBV and HCV infections.

Recovery effects of repeated exposures to normobaric hyperoxia on local muscle fatigue.

Reported recovery effects of hyeroxia are conflicted. This study aimed to identify the effects and the mechanisms of normobaric hyperoxia on the recovery of local muscle fatigue, which is the most commonly encountered form of fatigue both daily and in training and competitions. Twelve male subjects performed 3 × 3 × no less than 30 seconds of isometric quadriceps exercise at 70% of maximum voluntary isometric contraction (MVIC) separated by two 15-minute recovery sessions under 1 of 2 different atmospheric oxygen concentrations, one in normoxia (NOX; 20.

Evaluation of the spinal cord white matter.

Morphological findings or evaluations of the nervous system have traditionally concentrated on cell somata; evaluations of the white matter have not been put forward up to now. This study was conducted to evaluate the white matter in the spinal cord with the LPH discriminative staining method which was proposed by Goto. Thanks to the minimum shrinkage ratio (10 ± 0% in length) which this technique allows, it is possible to evaluate the sizes of nerve axons, and to compare the arrangement of nerve fibers in various parts of the spinal white matter.

Nuclei of the human raphe.

Along the raphe of the brain stem, a series of small neuronal groups can be observed in the medulla oblongata, the pons and the mesencephalon. The neurons located in and adjacent to the raphe are considered to produce mainly serotonin (5-HT). The groups of nuclei containing 5-HT were first reported in experimental animals in the early 1960s.

Morphometric and functional correlation of human neuronal somata: pyramidal motor, special sensory and general sensory systems.

Using an ideal tissue preparation method, we found a definite correlation between various human neuronal somata from the view point of accurate morphometry and functional evaluations. We believe this study may be of value, or even indispensable in the correct understanding of neurological symptomatology and phenomenology.

Morphological evaluation of the human pyramidal tract: tapering of axons.

It is generally accepted that nerve fiber conduction velocity is directly proportional to the fiber diameter under the condition, based on a supposition, that the transverse area of axons is normally maintained constant. Using an ideal preparation method for the purpose of axonal discrimination, we examined 43 human spinal cords after making transverse sections at the cervical, thoracic, lumbar and sacral levels and found a tapering of the axons in the lateral pyramidal tract, as the cross-sectional area of the pyramidal axons showed a definite decrease from the cervical to the sacral levels. Our results contradict the supposition that the transverse area of axons is normally maintained constant, which has for a long time been believed to be true without any evidence for it.

Morphological evaluation of the human pyramidal tract: gender and age differences.

Using a preparation method composed of secondary chromic acid fixation, nitrocellulose embedding and Luxol fast blue-PAS-hematoxylin stain (a discriminative staining method) for the purpose of axonal discrimination, we examined 43 human spinal cords (31 males and 12 females) at the C5 level to find the differences due to gender and aging in axons of the lateral corticospinal tract. These results can be of great help in understanding the motor functions in relation to gender differences and the aging process.

Morphometric evaluation of the aging process in various human nerve fibers.

We carried out a morphometric comparison of tissue sections from the human spinal cord, medulla oblongata, cranial nerves, autonomic nerves and spinal nerves with the help of a very accurate method that includes two-step fixation, nitrocellulose embedding and discriminative staining. We conducted morphometric evaluations to compare various axonal areas between different individuals using a combination of an image analyzer and a high power microscope. Our study showed a negative correlation between age and axonal area in all nerves except the greater splanchnic nerve.

Development of the human parvocellular red nucleus. A morphological study.

Morphology of the human parvocellular red nucleus (RNp) was investigated in 14 fetuses aged from 12 to 39 weeks of gestation (WG). The brains were processed into celloidin-embedded serial sections. At 12 WG, the anlage of RNp was observed as an ovoid mass of immature neurons clustering into some groups.

Comparison of preparation methods for the evaluation of nerve axons.

We have conducted a study to compare various preparation methods, including a certain number of new methods, to find which ones are best suited to the morphological evaluation of nerve fibers in the pyramidal tract of the human medulla oblongata. Our main concern was to find fixation and staining methods that would minimize errors, especially regarding the tissue shrinkage ratio and the ease of staining. From the two fixation methods we examined, the most satisfactory was the secondary chromic acid fixation (which gave the best overall results when followed by nitrocellulose embedding), as it gives the lowest shrinkage ratio with the narrowest range (10 +/- 0%).

Morphometric development of the posterior funicular nucleus in the human medulla oblongata.

Using serial sections of 11 human brains of fetuses 18-40 weeks of gestation (WG), 2-month-old infant and 63-year-old adult, we conducted the quantitative analysis of the development of the posterior funicular nucleus (PFN) in the medulla oblongata. The results suggest the following: (1) The cells of the human cuneatus lateralis nucleus are easily distinguished from those of the gracilis nucleus and cuneatus medialis nucleus because the neuronal somatic areas are the largest; the smallest neuronal areas are in the cuneatus medialis nucleus. (2) The development of the PFN occurs at least in four stages characterized by the degree of maturation of the neurons: (a) immature neuronal stage before 20 WG, (b) preparatory stage between (a) and (c), (c) accelerated development stage from 30 to 40 WG, and (d) postnatal stage.

Morphometric evaluations of the human nervous system.

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.).

Development of the human magnocellular red nucleus: a morphological study.

The development of the human magnocellular red nucleus (RNm) was studied in 20 fetuses at 12-39 weeks of gestation (WG). With microscopic observation on serial sections of the brain, we measured the profile area of a neuronal cell body. At 12WG, several islands of immature cells of the RNm appeared dorsal to the parvocellular red nucleus (RNp).

Morphometric comparison of human spinal cord anterior horn cells between the cervical and lumbar levels.

Morphometric comparisons of anterior horn cells (AHCs) were conducted between cervical and lumbar spinal cords in 29 cadavers. The sizes of the AHCs were always larger at the lumbar level than at cervical level irrespective of the age of the spicemens, but a decrease in size with age was observed at both levels. The correlation coefficient shows a larger decrease in numbers and volumes at lumbar level than at cervical level.

Morphological characteristics of nerve cells in the human general sensory system.

We conducted a study to compare morphological characteristics of various nerve cells in the sensory system. This sort of evaluation is indispensable for a better understanding of the nervous system in relation to clinical physiology and neurology.

Morphometric evaluation of posterior funiculus nerve fibers in relation to aging.

We morphologically evaluated the size of axons in the posterior funiculus in different age groups and examined the changes due to aging. In the past, such studies have been conducted at the cervical spinal cord (C6) level, and a decrease in the size and number of axons due to aging has been noted. The current study was conducted at the lower lumbar spinal cord (L2) level.

Morphometric comparison of human nerve cells: pyramidal motor system.

We compared morphological and morphometric data on various motor neurons in the human pyramidal system using the modified Klüver-Barrera staining method with extremely minimized shrinkage ratio and an image-analyzer. We classified motor neurons in the human pyramidal system into three groups according to the measurement data. This report may be of interest to better understand the process of nerve conduction in the human pyramidal system.

Morphometric evaluation of the human tractus solitarius.

We measured the cross-sectional area (CSA) of the human tractus solitarius (HTS) with the help of an image-analyzer system on a cross section of the upper part of the medulla oblongata in 44 Japanese cadavers (22 males and 22 females) and examined the relationship between age, sex and whether the subjects were dentulous or edentulous. The results showed no significant differences between the left and right sides of the HTS in either male or female subjects. However, the size of HTS decreased slightly with age in males but not at all in females, whereas tooth loss had a definite incidence on the size of HTS in females but not in male, as the CSA was smaller in edentulous females but not in edentulous males.

Morphometric comparison of human nerve cells: special sensory system.

We compared morphometric data on various nerve cells in the human special sensory system using the modified Klüver-Barrera staining method with an extremely minimized shrinkage ratio and an image-analyzer. According to the measurement data of cell-body sizes, we classified nerve cells of the various nerve nuclei in the special sensory system into three groups. These data are of interest to better understand the process of nerve conduction in the special sensory system.

Morphometric difference in the human maxillary nerve fibers between dentulous and edentulous jaw subjects.

This study was conducted to quantify the change in the number and size of myelinated nerve fibers of the maxillary nerve with tooth loss in humans. We carried out a morphometric analysis to compare the number and size of myelinated nerve fibers in the human maxillary nerve between four dentulous and four edentulous jaw cases. Our results indicated that the number of axons decreased by approximately 13,000 with tooth loss.

Aging process of myelinated nerve fibers in the human Lissauer tract.

We calculated numbers and axonal areas of myelinated nerve fibers in the Lissauer tract of the human lumbar spinal cord (L1) from the viewpoint of the aging process. We examined 20 human spinal cords from 13 males and 7 females, age ranging from 41 to 88 years old. We found that, although the number of nerve fibers showed no significant change in relation to the age of the subject, the axonal area of myelinated nerve fiber in the Lissauer tract did decrease with age.

A morphological comparison of cervical spondylotic myelopathy: MRI and dissection findings.

The number of people with functional disabilities has been increasing with the rapid changes of age structure in the overall population. One of the major causes of disturbances in daily activities is cervical spondylotic myelopathy (CSM). The transverse area and sagittal diameter of the spinal cord measured by MRI is reported to correlate with the clinical manifestations of CSM, the duration of the disease, and the speed of recovery after surgery in patients with CSM.

Development of the human cuneatus medialis nucleus: a morphometric evaluation.

The morphometric features of the development of the human cuneatus medialis nucleus (CMN) were examined using complete serial celloidin sections of 11 brains: nine fetal brains, the brain of a 2-month-old infant and that of a 63-year-old adult. The morphometric analysis revealed at least four stages in the development of the CMN characterized by the maturation of neurons: (1) immature neuronal stage, (2) preparatory stage, (3) accelerated development stage and (4) postnatal stage. The development of the human CMN accelerates after 32 weeks of gestation (WG), and postnatal qualitative maturation also occurs.