Ultrastructural distribution of endogenous immunoglobulin-G in human term amniochorion

Maternal immunoglobulin-G (IgG) is known to be transported across the placental syncytiotrophoblast during the period when the human fetus is incapable of manufacturing these defensive molecules. In this study we investigated the possible role of the amniochorion, that surrounds the amniotic cavity in which the fetus lies, in the transfer of immunoglobulin. Endogenous IgG was localised in the amniochorion by confocal immunofluorescence microscopy and by ultrastructural labelling of ultrathin frozen tissue sections using the protein A-gold technique. Immunoreactivity was identified in the extracellular matrix tissues and necrotic amniotic epithelial cells. Healthy amniotic epithelial cells and cytotrophoblast cells of the chorion laeve were devoid o endogenous IgG. These results suggest a possible non-specific paracellular transport pathway between cytotrophoblast cells, which may conceivably contribute to the acquisition of passive immunity by the fetus, and offer a rational explanation for the presence of small quantities of maternal IgG in the amniotic fluid.     

Ultrastructure of human amnion and amniotic plaques of normal pregnancy

Summary The fine structure of amniotic and amniotic-plaque epithelia has been studied from normal term pregnancies. The columnar/cuboidal amniotic epithelial cells usually have apical or central nuclei, some free ribosomes, patches of granular endoplasmic reticulum, juxtanuclear Golgi complexes, rod-shaped mitochondria, lipid droplets and some glycogen granules. They have short, blunt microvilli which frequently branch and bathe in the amniotic fluid. The lateral plasma membranes enclose tortuous intercellular spaces which are always interrupted by variously folded processes and desmosomes. The epithelial cells rest on a basal lamina and exhibit highly folded basal processes. The amniotic epithelial cells are neither distinctly Golgi and fibrillar types nor light and dark in appearance.Amnion from near the umbilical cord contains many microscopic and several large plaques. Similar structures are not found on the reflected amnion. The microscopic plaques are whitish and translucent, whereas the large ones are opaque. The large plaques vary between 1–3 mm in diameter, and are over 15 cell layers thick. Each large plaque has a main central region and edges continuous with either the microscopic plaque or the simple amniotic epithelium. The main region shows four zones, namely, stratum basale, stratum spinosum, stratum granulosum and stratum corneum. Such zones are not distinct at the edges. The fine structure of basal cells compares with the amniotic epithelial cells, but the cells of spinosum and granulosum layers possess variable amounts of tonofibrils, keratohyalin granules, free ribosomes and other cytoplasmic organelles and inclusions. The corneum cells are keratinized and are frequently separated by intercellular spaces. They slough into the amniotic cavity singly or as a sheet, and contribute towards the composition of the amniotic fluid. The plaques are of amniotic origin, and are not formed by adhesion of either squamous cells or fetal skin cells (masses of keratinized squames). The present observations suggest that the occurrence of amniotic plaques is normal. The presence of plaques may not be necessarily associated with fetal abnormality. However, increase in numbers of plaques may be caused by conditions of fluid imbalance. The homology and significance of plaques in eutherian mammals have been discussed.This research was supported by USPHS Grant AM-11376 and NIH Grant 69-2136.     

Scanning electron microscopy of the human cerebral ventricular system

Summary Scanning electron microscopy was used to assess the ultrastructural differences exhibited by the varigated ependymal lining of the near-term human fetal 4th ventricle. The central portion of the fourth ventricular floor, including the median sulcus is punctuated by numerous clumps of cilia. The density of cilia here is not as great as that described for other regions of the human cerebral ventricular system; accordingly, underlying substructure can be noted. There are distinct differences between ependymas that line the floor of the fourth ventricle with those of the adjacent area postrema. The latter region possesses not cilia, but instead exhibits a dense knap of microvilli. The ultra-architecture of the choroid plexus is relatively similar to that of other circumventricular organs with the exception that it possesses small isolated groups of cilia as well as microvilli. These findings are discussed with respect to the dynamics of local CSF movement and flow, ependymoabsorption and ependymosecretionSupported by U.S.P.H.S. Grant NS 08171.Career Development Awardee GM K04 70001.     

The human rete testis

Summary The human rete testis was examined with regard to 1) the number and distribution of entrances of seminiferous tubules, 2) the light microscopic topography and 3) details of the passages as revealed by scanning and transmission electron microscopy. In a newborn 1474 entrances were counted, approximately 50 % entering from the right and 50 % from the left of the central long axis. Three major subdivisions of the rete were distinguished and described: a septal (or interlobular) part represented by tubuli recti, a tunical (or mediastinal) part which is a true network of channels, and an extratesticular part characterized by dilatations (up to 3 mm wide) which we have called bullae retis. In SEM, cylindrical strands running from wall to wall in the tunical and extratesticular rete spaces are a prominent feature. We have called these chordae retis. They are covered by epithelium and are 5–40 m wide and 15 to more than 100 m long. They contain a peculiar tissue consisting of central myoid cells in a fibroelastic matrix. The smaller chordae are avascular. In the light of these findings the rete is interpreted as a highly complex myoelastic sponge. Its function is discussed.Supported in part by USPHS Grant HD-03752 and by a Senior Scientist Award from the Alexander von Humboldt-Stiftung which made the co-authorship possibleSupported by a grant from the Deutsche ForschungsgemeinschaftFor their kind support in supplying us with material, we are indebted to Dr. Janssen (Institut für Rechtsmedizin, Universität Hamburg), Dr. Mairose (Zentralkrankenhaus der Justizbehörde, Hamburg) and Dr. Hubman (Allgemeines Krankenhaus St. Georg, Hamburg). We thank Dr. Kaiser (Zoologisches Institut, Universität Hamburg) for his friendly, generous and competent help with the scanning electron microscopy. Ms. Joanna Davis gave invaluable help with the laborious reconstruction of the rete entrances     

Classification of human placental villi

Summary The classification of human placental villi was reviewed on the basis of material prepared by means of special methods. The material from in situ normal-term placentae was biopsied by aspiration into glutaraldehyde. The classification was made on the basis of light-microscopic observations of semithin sections, reconstructions from serial sections, and scanning-electron micrographs. The peripheral villous tree is roughly divided into stem (ramuli), intermediate and terminal villi. The intermediate villi may be further subdivided as mature and immature types, which are found between the stem and terminal villi. Some of the terminal villi possess a local specialization described as the neck region. The histological characteristics and the branching pattern of each type are described, and the basis of the proposed classification is discussed.The authors wish to acknowledge the technical help of Mrs. Elke Böhm     

Cytomorphological study on human submandibular gland following treatment with secretagogue drugs

Using specimens of human submandibular glands, we have investigated in vitro the morphological modifications induced by clozapine, a dibenzodiazepine derivative that is used in psychotic patients and that provokes hypersalivation, a side-effect of therapy. The effects of the drug, used alone or in combination with carbachol, have been compared with those observed after treatment with drugs acting on specific receptors. To quantify the response to stimulation, we have calculated (with statistical methods) the number of microvilli and microbuds (corresponding to pits seen in images obtained by transmission electron microscopy) per square micrometre of the cytoplasmic surface of the intercellular canaliculi luminal membrane in images obtained by high-resolution scanning electron microscopy. Clozapine, when directly acting on human submandibular specimens, induces a small secretory response in serous cells; this is partially decreased by muscarinic and adrenergic antagonists and by combined incubation with carbachol, thus confirming its behaviour as a partial agonist to muscarinic receptors. We also suggests that the drug acts on the nerve terminals contained within the glandular specimens.This work was funded by MIUR (Italian Ministry for University and Research) and COFIN.     

Scanning and transmission electron microscopy of human ejaculate spermatozoa with special reference to their abnormal forms

Summary Spermatozoa from fertile and infertile human ejaculates were observed under the scanning electron microscope. A parallel study of sections was performed by transmission electron microscope.The normal head shows under the scanning electron microscope vesicular elevations in the region of the acrosome and a smooth and rigid appearance corresponding to the postnuclear cap whose occurrence is confirmed under the transmission electron microscope. Immediately anterior to this cap a shallow furrow transverses the head. Duplicated, unusually large or small and deformed heads are found under the scanning electron microscope. Most of these abnormal heads show no surface structure suggesting an acrosome.The neck and middle piece are occasionally, though frequently in abnormal spermatozoa, covered by a cytoplasmic droplet. Otherwise, the mitochondrial sheath is recognized under the scanning electron microscope as a beaded thickening in the middle piece. The lack of mitochondria is manifested by a smooth middle piece thinner than the principal portion. Transmission electron microscopy of sections reveals various types of anomalies in the number of cores, core filaments and mitochondria embedded in the cytoplasmic droplets.Abnormalities in the principal portion of the tail such as duplication, unusual thickness and length are shown under the scanning electron microscope.The investigation indicates that scanning electron microscopy is suited for the clinical as well as cytological examination of human ejaculate spermatozoa.     

Ultrastructural analysis of the human cerebral ventricular system

Summary The ultrastructural organization of the human fetal choroid plexus was assessed with scanning electron microscopy. The membranous modifications of choroidal ependymal cells differ remarkably between 11 and 20 weeks of intrauterine development and suggest a variable functional capacity at different times of ontogenesis. Based upon existing data coupled with the ultra-architectural organization of cilia, clavate and linear microvilli are seen with scanning electron microscopy, a multiple functional role is hypothesized for choroidal ependymal cells.supported by USPH grant NS 08171.career development awardee K04 GM 70001     

Cytomorphometric analysis and surface ultrastructure of developing decidua

A scanning electron microscopic (SEM) and morphometric analysis of the topographical changes occurring in the uterine luminal epithelial layer in association with decidual tissue (DT) formation in guinea pigs was undertaken in order to elucidate the surface ultrastructural characteristics which occur during the process of endometrial differentiation. Experimentally induced decidua formation was promoted by mechanical stimulation of the antimesometrial luminal surface during the period of maximal uterine sensitivity to stromal differentiation. DT-associated remodeling of the uterine epithelial layer was subsequently examined by light and SE microscopic analysis for apical epithelial and luminal contour alterations associated with decidua growth. Cytological changes in the luminal surface associated with DT induction included sparse microvillus growth from the apical epithelial surface, accompanied by the appearance of prominent apical membrane surface protrusions and endometrial gland openings as compared with non-DT-stimulated control samples. Decidua surface growth was characterized by a short, sparse epithelial microvillus pattern present over a highly contoured luminal uterine surface on which contoured gland openings were both numerous and prominent. These surface modifications contrasted with the flat, non-decidualized luminal surface contour which was covered by distinct, microvilli-laden, apical cell membranes, and defined by prominent intercellular membrane borders. The uterine surface at the time of maximal DT formation (i.e. growth) closely resembled that of a uterine luminal surface undergoing apoptosis and subsequent cellular reabsorption, characterized by disrupted cell surface membranes, sparse microvillus surfaces and prominent epithelial contours reflecting stromal tissue and vasculature involution. These data indicate that the alterations in the uterine luminal surface associated with DT formation are reminiscent of the endometrial changes associated with the initiation of early placentation, and may be used as a model for the analysis of the role of epithelial cell surface modifications associated with the induction and support of interstitial blastocyst implantation and early decidua formation.     

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     

Scanning electron microscopy of human cerebellar cortex

Summary Scanning electron microscopy and cryofracture technique were applied to study neuronal architecture and synaptic connections of the human cerebellum. Samples were processed according to the technique of Humphreys et al. (1975) with minor modifications. The granule cells exhibit unbranched filiform axons and coniform dendritic processes. The latter show typical claw-like endings making gearing type synaptic contacts with mossy fiber rosettes. The unattached mossy rosettes appear as solid club-like structures. Some fractographs show individual granule cells, Golgi neurons and glomerular islands. The climbing fibers and their Scheibel's collaterals were also characterized. In the Purkinje layer the surface fracture was produced at the level of the Bergmann glial cells, which are selectively removed, allowing us to visualize the rough surface of Purkinje cells and the supra- and infraganglionic plexuses of basket cell axons which appeared as entangled threads. In the molecular layer the three-dimensional configuration of the Purkinje secondary and tertiary dendritic branches was obtained. The filiform parallel fibers make cruciform synaptic contacts with the Purkinje dendritic spines. The appearance of stellate neuronal somata closely resembled that of the granule cells. The subpial terminals of Bergmann fibers appeared attached to the exterior of the folia forming the rough surfaced external glial limiting membrane.     

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.     

人羊膜与人脱细胞羊膜形态结构的对比观察

目的：对比观察人羊膜（human amniotic membrane,HAM）脱细胞处理前后的形态结构变化,为人脱细胞羊膜（human acellu-lar amniotic membrane,HAAM）作为良好的生物支架材料提供依据。方法：取健康剖宫产孕妇的胎盘,剥离获取HAM,行HE染色、透射电镜（transmission electron microscope,TEM）、上皮面与基质面扫描电镜（scanning electron microscope,SEM）检测;将HAM经物理和胰蛋白酶等脱细胞处理后获得HAAM,亦行HE染色、TEM、上皮面与基质面SEM检测;最后将检测结果进行对比观察。结果：通过HE染色表明HAM的细胞成分去除干净;TEM断面观察HAAM表明其富含大量密集的呈点状、线状及条索状的纤维成分;SEM观察表明HAAM的上皮面与基质面呈现不同的三维结构,未见胶原纤维和网状纤维断裂。结论：HAM经脱细胞处理制备的HAAM,既去除了可引起移植排斥反应的细胞成分,又保存了完整的三维结构,为良好的生物支架材料。     

Three-dimensional architecture of the human myosalpinx isthmus

Summary The three-dimensional architecture of the human isthmic myosalpinx is directly visualized by means of scanning electron microscopy after removal of interstitial connective tissue through NaOH maceration and ultrasound microdissection. These investigations show that the myosalpinx is composed of irregularly running bundles of smooth muscle cells, changing their orientation within the myosalpinx and displaying longitudinal, oblique and circular directions. The muscular bundles anastomose and intermingle with other bundles running at different levels in the oviduct wall, and actually give rise to a wide and complex muscular network in which no distinct layers are readily discernible. These morphological data are consistent with the physiological findings that the transport of gametes and embryo in very early stages in the isthmic portion of the oviduct tube is the result of a discontinuous pattern of forward and backward movements.     

Biondi bodies in the choroid plexus epithelium of the human brain

Summary Scanning electron microscopy (SEM) was used to examine choroid plexuses in the brain of two human adults aged 44 and 46, respectively, and 12 older subjects from 67 to 98 years of age. It was possible to obtain a three-dimensional view of the ring-like structures (Biondi bodies) located in the cytoplasm of choroid plexus epithelial cells in the older-age group. The filaments forming the rings were clearly visible. No such structures were found between epithelial cells. The intracellular location of the Biondi bodies and their state of preservation compared to other cytoplasmic elements suggest that they may have a destructive effect on epithelial cells of choroid plexuses. The same material was examined by transmission electron microscopy (TEM); the results obtained were in full agreement with the evidence obtained with SEM.     

A comparative scanning electron microscopic analysis of the human cerebral ventricular system

Summary A scanning electron microscopic analysis of the adult human third ventricular wall revealed ultra-architectural differences between dorsal and ventral portions. In the brains of thirteen and sixteen week old human fetuses regional differences in the surface organization of lining ependyma were more sharply defined than those of the adult. Alterations in the luminal surfaces of ependyma may reflect differences in the functional capacity of various ventricular areas. The potential role of certain ependyma (tanycytes) and their putative participation in neuroendocrine events is discussed.Supported by U.S.P.H.S. Grant NS 08171.U.S.P.H.S. Career Development Awardee K 04 GM 70001.     

Antioxidant-mediated protective effect of potato peel extract in erythrocytes against oxidative damage

Potato peels are waste by-product of the potato processing industry. They are reportedly rich in polyphenols. Our earlier studies have shown that extracts derived from potato peel (PPE) possess strong antioxidant activity in chemical and biological model systems in vitro, attributable to its polyphenolic content. The main objective of this study was to investigate the ability of PPE to protect erythrocytes against oxidative damage, in vitro. The protection rendered by PPE in erythrocytes was studied in terms of resistance to oxidative damage, morphological alterations as well as membrane structural alterations. The total polyphenolic content in PPE was found to be 3.93 mg/g powder. The major phenolic acids present in PPE were predominantly: gallic acid, caffeic acid, chlorogenic acid and protocatechuic acid. We chose the experimental prooxidant system: FeSO₄ and ascorbic acid to induce lipid peroxidation in rat RBCs and human RBC membranes. PPE was found to inhibit lipid peroxidation with similar effectiveness in both the systems (about 80–85% inhibition by PPE at 2.5 mg/ml). While PPE per se did not cause any morphological alteration in the erythrocytes, under the experimental conditions, PPE significantly inhibited the H₂O₂-induced morphological alterations in rat RBCs as revealed by scanning electron microscopy. Further, PPE was found to offer significant protection to human erythrocyte membrane proteins from oxidative damage induced by ferrous–ascorbate. In conclusion, our results indicate that PPE is capable of protecting erythrocytes against oxidative damage probably by acting as a strong antioxidant.     

Three-dimensional development of luminal projections and junctional complexes in the developing central nervous system blood vessels of the rat

Summary The luminal surface features and Junctional complexes from developing blood vessels in the rat central nervous system have been studied by high-voltage electron microscopy and scanning electron microscopy. Developing blood vessels exhibit three types of luminal projections; marginal folds or ridges at Junctional complexes, ridges not at Junctional complexes and microvilli. Both types of ridges are associated with troughs or depressions in the luminal surface of the endothelial cell. Those ridges not associated with Junctional complexes take part in the production of enclosed tunnels in the endothelial cell cytoplasm. Fusion of the external leaflets of Junctional complexes between adjacent endothelial cells occurred, initially, near the luminal surface of the blood vessel with other small fusion sites forming in the direction of the basal lamina secondarily. Further fusion activity to produce the zonula occludens type junction appeared to spread outwards from the smaller fusion sites.Supported in part by a NIH HVEM Travel Grant and the Medical College of Georgia     

Quantitative electron microscopic studies on the innervation of the human thymus

Summary Quantitative electron microscopic studies have been carried out on the human thymus. According to the equation L _v =(2n)/F (Hennig, 1963) we have calculated that there is less than 0.204 mm nerve per 1 mm³ thymus tissue inside the blood-thymus-barrier (level of significance of 0.95). This result is compared to the degree of innervation in brown adipose tissue, which contains more than 160 mm nerve per 1 mm³ tissue. The biological significance of the paucity of neuronal elements in the thymus is undetermined.We are much obliged to Dipl. Ing. Dr. A. Hennig for his advice in the mathematical evaluation of our results.We are also indebted to Dr. med. A. Krug (Chir. Universitätsklinik Kiel) for human thymus material.This investigation was supported by the Deutsche Forschungsgemeinschaft.     

A combined scanning and transmission electron microscopic study and electron probe microanalysis of human pineal acervuli

Summary Untreated, decalcified and trypsinized acervuli from human pineal bodies were studied with the scanning and transmission electron microscope as well as by electron probe microanalysis. The mulberry-like acervuli are composed of a various number of spherical lobes (135–800 m) between which clustered groups of globuli (4–14 urn in diameter) are observed. The acervular lobes are very probably formed by an aggregation of these globuli. Small round particles 125–500 Å in diameter are observed on the surface of the pineal concretions. These are not influenced by either decalcification or trypsin treatment. The acervular mineral corresponds morphologically to hydroxyapatite. The electron probe microanalysis reveals the existence of calcium and phosphorus as main components of the acervuli. Small quantities of magnesium and strontium were also detected.Dedicated to Professor Berta Scharrer on the occasion of her 70th birthdayWith the technical assistance of Mr. P.A. MilliquetThe author wishes to thank Mr. Bauer and Mr. Fryder (Nestec SA, La Tour de Peilz) for the use of the Cambridge Stereoscan electron microscope and Dr. T. Jalanti (C.M.E., Lausanne) for his help with the use of the X-ray microanalyser