Three-dimensional Fine Structures Research Articles

Pathogenesis of Reinke's Edema of the Vocal Fold.

The most frequent etiologic factor of Reinke's edema (RE) is considered to be smoking. However, the mechanism for the onset and development of the disease remains unclear. Hypoxia-inducible factor-1α (HIF-1α) is an oxygen-dependent transcriptional activator which plays crucial roles in angiogenesis in hypoxic microenvironments. HIF-1α induces the expression of vascular endothelial growth factor (VEGF) which involves angiogenesis and enhances vascular permeability. This study investigated the roles of HIF-1α in the pathogenesis of RE. Surgical specimens of RE from patients who underwent endolaryngeal microsurgery were used. Normal vocal folds were used as a control group. Expression of HIF-1α and VEGF was analyzed by immunohistochemistry. Three-dimensional fine structures of the vessels in RE were investigated using correlative light and electron microscopy (CLEM) technique. HIF-1α and VEGF were broadly expressed in the stromal, inflammatory, and endothelial cells in the lamina propria of the vocal fold of RE. The expression of HIF-1α and VEGF of RE were significantly higher than in the lamina propria of the normal vocal fold mucosa. CLEM showed vascularization and telangiectasia and there were many dilated capillaries with thin endothelium not covered with pericytes indicating the vessels were fragile. Transcription factor HIF-1α and induced VEGF likely play roles in the pathogenesis of RE. And increased vascular permeability with fragile vessels in angiogenesis is likely to be an etiology of RE. Transcription factor HIF-1α and induced VEGF are potential therapeutic targets for RE. NA Laryngoscope, 134:1785-1791, 2024.

Three-dimensional fine structures in deep fascia revealed by combined use of cryo-fixed histochemistry and low-vacuum scanning microscopy

Recent physiological studies have shown that the deep fascia has received much attention concerning clinical medicine; however, histological examination of the deep fascia has not been well established. In this study, we aimed to clarify and visualize the structure of the deep fascia by taking advantage of cryofixation techniques and low-vacuum scanning electron microscopy. As a result, the ultrastructural observations revealed three-dimensional stratification of the deep fascia composed of three layers: the first superficial layer consisting of collagen fibers extending in various directions with blood vessels and peripheral nerves; the second intermediate layer formed by single straight and thick collagen fibers with flexibility; and the third deepest layer, consisting of relatively straight and thin collagen fibers. We explored the use of two hooks to hold a piece of deep fascia in place through the course of cryo-fixation. A comparative observation with or without the hook-holding procedure would indicate the morphological adaptation to physiological stretch and contraction of the deep fascia. The present morphological approach paves the way to visualize three-dimensional ultrastructures for future biomedical studies including clinical pathophysiology.

Three-dimensional fine structures of the maculae flavae of the human vocal fold using correlative light and electron microscopy.

To analyze various aspects of complex tissue, there is increasing demand to study each sample at different length scales in biology. Correlative light and electron microscopy (CLEM) is the latest technique to correlate two different types of information on the exact same histological area of interest: histology (from light microscopy) and ultrastructure (from electron microscopy). The three-dimensional fine structures of the maculae flavae (MFe) of the human vocal fold were investigated using CLEM. Five normal human adult vocal folds as specimens embedded in paraffin, sectioned, and mounted on glass slides with/without a chemical digestion method (modified sodium hydroxide maceration method) were investigated. Observations using CLEM were performed. The fine structures of cells and extracellular matrices in the MFe and their peripheral regions were able to be observed on the exact same histological area of interest with the light microscope and field emission-scanning electron microscope. Cobblestone-like polygonal cells, vocal fold stellate cell-like cells, and fibroblast-like spindle cells were intermingled in the MFe of the human vocal fold. The extracellular matrices surrounding each three types of cell in the MFe differed, suggesting the cells were different in functional property. CLEM is a useful technique to observe the three-dimensional fine structures of the human vocal fold mucosa. The results of the present study are consistent with the hypothesis that the cells in the MFe of the human vocal fold have heterogeneity and each three types of cell have different properties.

Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source.

We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

Nanometer resolusion three-dimensional microprobe RBS analyses by using a 200 kV focused ion beam system

Three-dimensional Rutherford backscattering (RBS) analyses have been achieved in the nanometer range for both lateral and vertical resolution using a 200 kV focused ion beam (FIB) system. The ion-optical design of the FIB microprobe RBS analysis system in Osaka University has been modified, and it is confirmed that the focusing performance of less than 20 nm lateral resolution is obtained with 300 keV Be 2+ ion beam. Three-dimensional microprobe RBS analyses have been performed on a sample that has a structure with 2 layers of 10 nm thick Pt gratings separated vertically by a 25 nm thick SiO 2 layer and offset 90° each other. The Pt gratings consist of 0.5 μm width lines and 2 μm intervals. The RBS mapping and tomography images clearly show the three-dimensional fine structures of the sample.

Micro heat pipes in low temperature cofire ceramic (LTCC) substrates

With projected power densities above 100 W/cm/sup 2/ for devices, new methods for thermal management from the heat generation at the die to heat removal to the ambient must be addressed. By integrating micro heat pipes directly within the ceramic substrate, effective thermal conductivity for spreading heat in both radial and axial directions was achieved. New materials and processes were developed to fabricate the unique components required to handle high thermal loads. Enhanced thermal vias to minimize the thermal impedance through the ceramic in the evaporator and condenser sections were developed, increasing the effective thermal conductivity from 2.63 to near 250 W/m-/spl deg/C. The use of an organic insert fabricated into the desired complex shape using rapid prototyping methods, coupled with the viscoelastic flow of the low temperature cofire ceramic (LTCC) during lamination, allowed complex shapes to be developed while ensuring uniform green tape density during lamination prior to tape firing. Large cavities, three-dimensional fine structures and porous wicks for capillary 3-D flow have been utilized to fabricate the heat pipes. Heat pipes and spreaders, utilizing water as the working fluid, have been demonstrated operating with power densities in excess of 300 W/cm/sup 2/.

Surface Structures of Cultured Type 2 Astrocytes Revealed by Atomic Force Microscopy

Abstract The incomplete morphological characterization of type 2 astrocytes is in part responsible for the slow progress of studies on these cells. To examine and characterize type 2 astrocytes morphologically, three-dimensional fine structures of the surfaces of type 2 astrocytes cultured from rat cerebella were studied by a combination of atomic force microscopic and immunocytochemical techniques. Atomic force microscopy (AFM) revealed irregular ridge-like structures that form a meshwork distributed throughout the cell body surfaces and the thick processes. These ridges were found to be of two heights (31 nm and 82 nm). This finding indicates two possible configurations responsible for shaping the meshwork: (1) two structures of different thickness are beneath the cell membrane; and (2) two structures are located at two different depths from the cell membrane. On the other hand, immunocytochemical studies for tubulin and glial fibrillary acidic protein (GFAP) revealed that these cytoskeletal filaments a...

Photoforming Applied to Fine Forming

The photoforming process is one of the optical forming methods used to produce plastic models. It has unique features such as the ability to form various objects, with few restrictions on shape, and to process them quite simply. In this paper, computer simulation considering photon behavior in liquid resin clarified that fine control of the exposure dose, that is, the light energy applied to a unit area of the surface, and soft focusing are the keys to achieve high precision. Some results of experimental forming demonstrate the possibility of producing fine structures with a forming resolution within 10μm. Finally, the results of this study suggest that this process can be applied to the construction of three-dimensional fine structures and precise mechanisms.

Three‐dimensional organization of neuronal and glial processes: High voltage electron microscopy

Neurons and glia cells in the mammalian central nervous system have many complicated processes. They are too fine for light microscopic study and too complicated and widely spread for thin section electron microscopy. High-voltage electron microscopic (HVEM) stereo observation of thick Golgi preparation provides detailed 3-D images of their processes. Three-dimensional fine structures of astocytic processes in the neuropile and on the surface of neuronal somata, and those of the ruffed cell axon initial segment and thorny excrescences of CA3 pyramidal cell dendrites, are elucidated with the aid of HVEM stereoscopy of thick Golgi preparations. In addition, some results obtained by 3-D morphometrical analysis of dendritic spines using HVEM stereo images are shown. The examples presented here clearly show the usefulness of high-voltage electron microscope stereo observation of thick specimens for detailed morphological and morphometric study of the central nervous system.

Photoforming Applied to Fine Forming.

The photoforming process is one of the optical forming methods for making plastic models. It has the unique features of shaping various ebject forms very freely and processing them quite simply. In this paper, a computer simulation considering photon behavior in liquid resin shows that light amount control and rather soft focusing are the important things to achieve high precision. Then, some results of experimental forming demonstrate the possibility of making precise structures with a forming resolution within 10 μm. Finally, this paper suggests that this process can be applied to the construction of three-dimensional fine structures and precise mechanisms.

High energy, high resolution monochromatic x-ray computed tomography system

We have developed a high energy, high resolution monochromatic x-ray computed tomography system using synchrotron radiation. Our system is installed in a vertical wiggler beamline at the Photon Factory of the National Laboratory for High Energy Physics that can produce high brilliance x-rays in the high energy region. At the present stage, we have obtained monochromatic x-rays up to 75 keV, succeeded in taking computed tomography images of materials up to 50 keV with large absorption coefficients that could not be imaged by conventional methods, and observed three-dimensional fine structures in such materials. When the K-edge subtraction method was applied, the system could quantitatively and nondestructively measure the trace distribution of a specific element in the object of interest. In this paper we introduce the experimental system, mainly the crystal monochromator, evaluate the results, and discuss the performance of the system.

High Energy, High Resolution Monochromatic X-ray Computed Tomography System

Abstract We have developed a high energy, high resolution monochromatic x-ray computed tomography system using synchrotron radiation. Our system is installed in a vertical wiggler beamline at the Photon Factory of the National Laboratory for High Energy Physics that can produce high brilliance x-rays in the high energy region. At the present stage, we have obtained monochromatic x-rays up to 75 keV, succeeded in taking computed tomography images of materials up to 50 keV with large absorption coefficients that could not be imaged by conventional methods, and observed three-dimensional fine structures in such materials. When the K-edge subtraction method was applied, the system could quantitatively and nondestructively measure the trace distribution of a specific element in the object of interest. In this paper we introduce the experimental system, mainly the crystal monochromator, evaluate the results, and discuss the performance of the system.

Maskless ion implantation system for three-dimensional fine doping structures in III–V compound semiconductors

We will report on focused ion beam (FIB) implantation system technology for III–V compound semiconductors, a versatile microfabrication process in UHV, which is suitable for constructing three-dimensional fine doping structures with arbitrary impurity and geometry without using masks. To realize this, the key technology for controlling such ion beam parameters as impurity species, doping energy, and ion beam diameter/position, while maintaining minimum astigmatism of the FIB is described. Based on the control technology, three-dimensional pattern doping structures are fabricated by iteration of growing an MBE GaAs layer followed by implanting FIB, arbitrarily choosing such impurity ions as Be (p-type) and Si (n-type).

A scanning electron microscopic study on the liver of mice.

The three-dimensional fine structures of several tissue components of the liver in normal mice were studied by scanning electron microscopy. The tissue components observed were as follows: hepatocytes, sinusoidal endothelial cells, the Kupffer cells, fat-storing cells, reticulin fibers and epithelial cells of the bile duct. Two types of fenestrations were found in the sinusoidal endothelial cells. One was smaller and clustered, and the other larger and scattered. Both of them were distributed equally throughout the hepatic lobule. Intercellular gaps were found at the endothelial junction. The Kupffer cell which was localized in a large gap between the endothelial cells was characterized by numerous villous projections, and by the absence of fenestrations which were observed in the endothelial cells. Fat-storing cells were located between hepatocytes. They elongated their processes into the space of Disse, but never protruded into the sinusoidal lumen. They were clearly distinguished from the endothelial cells and the Kupffer cells by their morphological feature and location. No transitional form was seen among the endothelial cells, the Kupffer cells, and the fat-storing cells.