Three-dimensional organization of lymphatics and its relationship to blood vessels in rat small intestine

Summary The lymphatic organization and its relationship to the vascular system in the rat small intestine was studied by scanning electron microscopy of corrosion casts and freeze-fractured tissues, and by light microscopy of injected preparations. The villus possessed 3–10 or more central lacteals depending upon the villous width. The lacteals in each villus possessed interconnections between adjacent ones and were surrounded externally by the villous capillary network. At the villous base, the lacteals fused and formed a wide sinus, from which 2 or 3 lymphatics descended and led into the submucosal ones. In the muscularis externa there was a coarse lymphatic network which, together with the submucosal one, drained into collecting lymphatics continuous with the mesenteric ones. The central lacteals and the sinus were lined with thin endothelial cells with cytoplasmic leaves interdigitating with those of adjacent ones. There were tissue channels in the villous interstitial space, which opened through the gaps between the lymphatic endothelial cells into the central lacteals.The voluminous lacteals in the villi suggest their great potential for lymph formation. The existence of collecting lymphatics with valves in the muscularis externa suggests that contraction of the layer is involved in transporting lymph towards the efferent lymphatics.     

Three-dimensional aspects of blood vessels in thyroids from normal,low iodine diet-treated,TSH-treated,and PTU-treated rats

Summary Three-dimensional images of blood vessels in thyroid glands from normal, low iodine diet-treated, thyroid-stimulating hormone (TSH)-treated and propylthiouracil (PTU)-treated rats were investigated by use of the corrosion-cast method. The vascular casts made by the injection of methacrylate resin were observed with the scanning electron microscope. In normal animals, each follicle is surrounded by a clearly defined basket-like capillary network, which is generally independent of adjacent networks, though a few anastomoses or common capillaries are sometimes seen. In low iodine diet-treated or TSH-treated animals, the capillaries in the basket-like network become markedly dilated and fuse with one another. Though the vascular casts of PTU-treated animals are similar to those of low iodine diet-treated or TSH-treated ones in some aspects, most basket-like networks become distorted and irregular in shape, and the capillaries are heterogeneously dilated and show many buds, branches and anastomoses. We consider that these peculiar changes in the thyroid of the PTU-treated animals are due not only to the elevation of serum TSH but also to other unknown factors. It is clear that the distribution and morphology of the thyroid capillaries are extremely affected and changed by functional states of the gland.This study was supported in part by grant from the Research Fund of the Ministry of Education, Science, and Culture, Japan     

Innervation of the arteriovenous anastomoses in the dog tongue

Summary Profiles of nerve plexuses in the arteriovenous anastomoses of the dog tongue were investigated by both transmission and scanning electron microscopy. Three-dimensional morphology of the vascular nerves was examined after removal of the connective tissue components by the HCl-hydrolysis method. Tight bending and a rich nerve supply were the most characteristic features of the anastomosing channels. The tunica media consisted of an outer circular layer of typical smooth-muscle cells and an inner region containing longitudinal plicae of ramified smoothmuscle cells. The tunica adventitia was exclusively occupied by nerve bundles; fibroblasts were poorly developed. Numerous nerve bundles of variable size were coiled around the anastomosing channels, and occasional bundles ran crosswise over the U-shaped bent vessels.     

Arteriovenous anastomoses in the cat carotid body

Summary In artery surrounding areas in the periphery of the carotid body of the cat we found arteriovenous anastomoses differing in respect to their character. So far, it is not yet to decide the frequency of their occurrence and their functional significance. The anastomoses were demonstrated by light microscopy of serial sections and by scanning electron microscopy with a more developed corrosion casting technique.

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Zusammenfassung In den arteriennahen, peripheren Bereichen des Glomus caroticum der Katze wurden arteriovenöse Verbindungen nachgewiesen, die ihrem Charakter nach unterschiedlich sind. Es ist allerdings noch nicht zu entscheiden, ob derartige Anastomosen regelmäßig vorkommen und wie sie funktionieren. Die beschriebenen Gefäßverbindungen konnten lichtmikroskopisch anhand von histologischen Serienschnitten und mit Hilfe einer weiterentwickelten Korrosionstechnik im Rasterelektronenmikroskop dargestellt werden.

     

The Surface structure of isolated pancreatic islet cells

Summary The surfaces of isolated pancreatic islet cells were studied with the scanning and transmission electron microscopes. Islets were isolated from the pancreas of Wistar rats by collagenase treatment and were incubated either in glucose-free medium or in 300 mg% glucose for one hour. Immunoreactive insulin (IRI) in the media of both control and experimental preparations was assayed. Islets were then transferred to 4% glutaraldehyde, buffered with cacodylate, pH 7.4, and prepared for scanning and transmission electron microscopy. Cell masses average 200 in diameter. Alpha cells appear pyramidal in shape, are about 8 in diameter and appear in groups. Beta cells are round or oval in shape and have an average diameter of 10 . Glucose stimulation raised the IRI value tenfold and increased the number of blebs and other surface irregularities per unit area of beta cell surface. Comparison with transmission electron micrographs suggests that the blebs are related to the process of emiocytosis.Supported by U.S.P.H.S. Grant AM-10151.     

On the development of midpiece mitochondria of mouse spermatozoa

Summary As seen by scanning electron microscopy, the mitochondrial helix in the developing midpiece of mouse testicular spermatozoa is dextral in direction and consists of spherical mitochondrial units arranged in an orderly array of four units per gyre: three appearing in face view and a fourth hidden from view at the back of the gyre. As the spermatozoa mature, the dextral helix is transformed into a sinistral helix. Its constituent spherical mitochondria either change direction abruptly without changing shape; or having first become semilunar or diamond-shaped, they change direction gradually. Mitochondrial division follows the change in helical pitch producing a double sinistral helix. The spherical (or semilunar/diamond-shaped) mitochondria presumably elongate to form the units of the mature midpiece.     

Aggregation-induced alterations in fibroblast morphology

Summary The different stages during aggregation of diploid human skin fibroblasts have been examined by transmission and scanning electron microscopy. As a result of aggregation, fibroblasts form a complex tissue configuration. Numerous intercellular junctions can be observed, while the cells remain polygonal and do not develop an organised intracellular cytoskeleton. Cell division occurs only rarely. After aggregation, signs of progressive auto-digestion develop.Adhesion to a substrate results in outgrowth of the cells and monolayer formation, even when extensive cell damage had occurred. The morphology of fibroblasts in aggregates and in the monolayers, from which they were derived, is compared and the contribution of the aggregate system to the study of fibroblast behavior is discussed.J.J. Cassiman is Aangesteld Navorser van The National Foundation for Scientific Research, Belgium     

How cells settle on glass: A study by light and scanning electron microscopy of some properties of normal and stimulated macrophages

Summary Some properties of normal and stimulated peritoneal macrophages have been studied using light microscopy, cinemicroscopy, and scanning electron microscopy. No difference in the overall rate of translational movement was found between normal and stimulated cells. Macrophages were found to settle on glass by a process involving initial protrusion of very fine finger-like processes, followed by veils. Full extension occurred sooner in stimulated cells.We are grateful to Professor R. Barer for his criticisms, to Miss Anne Edwards for technical help, to Mr. G. Tuck for help with cinemicroscopy, and to the Science Research Council and the Medical Research Council for grants.     

鳋科（寄生桡足类）胸板的扫描电镜比较研究

本文利用扫描电镜观察了我国鳋科的5个属的种类。首次发现在它们的胸部腹面游泳足连接板之下均有一板状结构,其形状与栉齿的着生情况在不同属之间存在着明显的差异,同属不同种之间也不尽相同,这是一个过去未曾被注意过的结构,权且称之为胸板。它是一个独立的结构,不与连接板相连。胸板上的栉齿从形态-功能-适应三位一体分析,它与附着寄主有夭,以免被水流冲走,与无栉齿的相比,应是一个进步性状。     

蜱类染色体的分带研究和扫描电镜观察

在蜱螨亚纲（Ａｃａｒｉ）中,首先开展染色体分带研究及组型分析,发现了３种蜱的内多倍体,Ｃ分带证明,森林革蜱,草原革蜱,微小牛蜱的全套染色体国端丝粒,用扫描电镜观察了日本血蜱,微小牛蜱染色体的亚微结构,发现日本血蜱的染色体呈凹凸相同弹簧样螺旋结构,螺旋凹陷处相当于光镜下Ｇ带深带,螺旋隆起部相当于Ｇ带浅带,凹凸程度似乎不加入人类染色体的明显,还报告了草原革蜱,银盾革蜱,缺角血蜱及雌性森林革蜱,雌性日本     

LM and SEM study on the swordfish (Xiphias gladius) tongue

Swordfish (Xiphias gladius L. 1758) is a predatory and migratory fish. Its characteristic feature is a flat and sharp upper jaw forming a “sword”. The adaptation of vertebrates, including fish, to their environment is strictly related to the capacity of feeding and is carried out by often severe modifications of the anatomy of the buccal cavity, especially of the tongue. The aim of this study is, using light and scanning electron microscopy and considering that no data are so far available about the morphology of the tongue in this species, to analyse the anatomical characteristics of the tongue, especially its dorsal surface. The tongue shows a triangular shape and an apex, a body and a root. By SEM the presence of several small denticles and filiform papillae on the latero-ventral body was demonstrated while no taste buds or other sensitive structures are observed. LM shows a squamous stratified epithelium, becoming simple cuboidal around the denticles. Therefore this study could add further data to the knowledges of the fish oral cavity morphology supporting the hypothesis that the modifications and evolution of the tongue anatomy are, also in fish, related to the environment and especially to the feeding habits.     

多房棘球绦虫光镜及扫描电镜的观察

本文对甘肃漳县草滩乡家犬小肠所获检的棘球绦虫,做了光镜及扫描电镜(SEM)观察。根据其形态特征及流行病学资料,初步认定为多房棘球绦虫(Echinococcus multicularis)。对扫描电镜所记述的多房棘球绦虫成虫不同部位的表面微毛的形态结构做了较为详细的观察和比较;此外还观察了成熟节片侧缘生殖孔及孕节片内虫卵表面的超微结构。     

Three-dimensional organisation of the vasculature of the rat spermatic cord and testis

Summary The vascular architecture of the rat testis and spermatic cord was studied by a corrosion cast technique combined with scanning and transmission electron microscopy, and light microscopy. The casts preserve the endothelial impressions of the vessels and enable them to be differentiated into the various vascular components. Frequent arterio-arterial anastomotic arcades and occasional arterio-venous anastomotic channels are seen. A well defined hexagonal pattern of intertubular and peritubular vessels surround the seminiferous tubules. Prominent large endothelial nuclei protrude into the arterial lumina at branching sites, but their functional significance is not known. The outermost vascular layer of the testis consists of large veins, venules, and capillaries, but lacks any arterial branches; it also contains loosely arranged veno-venous anastomotic networks. We have named this vascular layer the sub-albugineal venous plexus. The testicular artery increases in luminal diameter as it approaches the testis. The periarterial capillary plexus, which lies between the pampiniform plexus and the testicular artery, is drained by two types of venules.     

Observations on the marginal ruffles of an established fibroblast-like cell line

Summary LW13K2 cells, a clone of a spontaneously in vitro transformed derivative of embryonic Lewis rat fibroblastic cells, were studied by phase contrast cine-light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ruffles found at the advancing edge of cells grown on glass substrates in vitro form and recede in a period of less than one min if they do not make an attachment of the substrate. If they fail to make an attachment they may form pinocytotic channels near the leading edge as described by Price (1972) and/or collapse, generally backwards, towards the cell body. The spines which appear to reinforce the membranous ruffles are the last structures to disappear, and accumulate in an irregular array behind the ruffling edge; this area is behind that in which pinocytosis occurs. In comparison with the sparse numbers of ribosomes found in the trailing edge, they are present in notable concentrations near the leading, ruffling edge of the cell. No membrane vesicles have been found in or near the ruffling edges at the ruffle-spine concentration zone.     

Morphological alterations of Pseudomonas aeruginosa and Escherichia coli by nocardicin A

Abstract Pseudomonas aeruginosa and Escherichia coli were exposed to nocardicin A, and were subsequently observed with transmission and scanning electron microscopes. Although the nocardicin A-induced morphological alterations such as bulges and spheroplast formations were observed both in P. aeruginosa and E. coli , their positions on the cell surface were different in the two species.     

Molar microwear in extant small-bodied faunivorous mammals: An analysis of feature density and pit frequency

This study quantitatively examined molar microwear in nine species of extant small-bodied faunivorous primates and microchiropterans. Comparative analyses were performed within the food category faunivory, both between hard- and soft-object feeding faunivores and between primarily insectivorous and carnivorous taxa. Additionally, microwear in faunivores was compared to that reported in the literature for frugivorous and folivorous primates. The results indicated that although insectivores and carnivores could not be distinguished by microwear analyses, hard-object faunivores (i. e., those that primarily consume beetles or actively comminute bone) can be readily distinguished from soft-object faunivores (i. e., moth, caterpillar, or vertebrate flesh specialists). The hard-object faunivores consistently exhibited greater pit frequencies (in excess of 40%). Furthermore, comparisons of these microwear data on faunivorous mammals to previous work on frugivorous and folivorous primates (Teaford, 1988, pers. comm.; Teaford and Runestad, 1992, pers. comm.; Teaford and Walker: American Journal of Physical Anthropology 64:191–200, 1984) permitted three observations to be made. 1) Faunivores tend to have higher mean feature densities than either frugivores or folivores, although these differences are not consistently statistically distinct. 2) Faunifores and frugivores that feed on hard-objects have comparable mean pit frequencies. 3) Although it is impossible to distinguish faunivores and folivores on the basis of metric analysis of gross molar morphology, this distinction can be made on microwear criteria. Both hard- and soft-object faunivores exhibit much higher mean pit frequencies than primarily folivorous species. © 1993 Wiley-Liss, Inc.     

Scanning electron microscope studies of some internal surfaces in human skin

Summary The scanning electron microscope has been used to investigate the surfaces of epidermis, hair follicles, fat cells, glands and blood vessels in sections of human skin. The appearances of structures associated with these surfaces have been described. The results demonstrate that this new instrument can become an important tool in the investigation of surface changes that might accompany the application of loads (extensive, compressive or torsional), or physiological or pathological abnormalities.We wish to thank Prof. R. M. Kenedi for his continued encouragement of this work. One of us (I.A.B.) is also grateful to the Science Research Council for the provision of a post-graduate student grant.