Characteristic Fine Structure Research Articles

ULTRASTRUCTURAL RELATIONSHIPS BETWEEN DECIDUA, TROPHOBLAST AND LYMPHOCYTES AT THE BEGINNING OF HUMAN PREGNANCY

Between the 20th and 40th day of pregnancy, human decidual cells in the endometrial connective tissue come into direct contact with the trophoblastic cells eroding the stromal tissue. Fibrillar deposits of maternal origin were randomly distributed between the maternal and fetal sites and did not form a continuous barrier. Structural features were prominent in the maternal and embryonic cells. Large decidual cells were intermingled with trophoblastic cells, and there was little intercellular material. Small developing decidual cells arose around the maternal precapillary arterioles and capillaries and were closely accompanied by lymphocytes. Fully developed decidual cells exhibited a fine structure characteristic of a state of active secretion, and trophoblastic cells gave structural indications of producing protein. The aggregates of decidual and trophoblastic cells in the human endometrium during early pregnancy ('deciduotrophoblastic complex') may function as a local humoral regulator releasing chemical factors and partaking in the establishment of immunological privilege at implantation.

Mammary and Extramammary Paget's Disease

SUMMARYTwo cases of mammary and one case of vulval Paget's disease are studied histologically and electronmicroscopically. There are no substantial morphological differences between those two types.The Paget cell has a characteristic fine structure: it lacks tonofibrils and shows many of the features of apocrine cells. Less highly differentiated keratinocytes lie adjacent to Paget cells and desmosomes exist between them. These observations suggest that Paget cells differentiate in situ from epidermal cells.

Entwicklung des Peristoms von Funaria hygrometrica

The Development of the double peristome (endo- and exostome) in Funaria hygrometrica starts just at the beginning of capsule differentiation. The first indication is a membraneous character of the middle-lamellae-region in the outer peristome (exostome), which becomes more and more significant during ripening of the peristome. This layer is similar to the lamellate layer between exine and intine during sporoderm development of microspores of various angiosperms. About ten days later the differentiation of the outer wall layer of exostome starts, forming the so-called „hygroscopic apparatus” with characteristic fine structure. This development will be finished morphologically at the time of meiosis of the spore mother cells or a little bit later, but always then when the potential germination-rate of the spores is raising. The endostome shows no „hygroscopic apparatus.” The region of the middle lamellae shows a characteristic fine structure different from that of exostome. It looks like a chain of pearls of various size. Each single oval particle seems to be surrounded by a unit membrane.

Resonance paramagnetique electronique du manganese divalent dans ZnAl 2O 4

The electron paramagnetic resonance spectrum of a single crystal of ZnAl 2O 4 (spinel structure) doped with manganese displays a fine structure characteristic of a purely cubic crystal field. Contrary to MgAl 2O 4: Mn 2+, where the degree of inversion is sizable, ZnAl 2O 4 therefore is a normal spinel.

Viscoelastic response of intervertebral disks at audiofrequencies.

The viscoelastic responses of intervertebral disks taken from the cervical regions of the spinal columns of several adult, male, mongrel dogs have been determined. The results are presented in terms of a mean complex shear compliance,Jd*=J′d−iJ″d, for the disk structures when these are subjected to small-amplitude audiofrequency vibrations (25–5000 Hz) while surrounded by normal salt solution, both at room temperatures and at 98·6°F (37.0°C) (in vitro). Values of the general compliance levels decrease with time after sacrifice, and an abrupt transition in the 100-Hz compliance-time curves at 5·5 hours after death is attributed to the completion of rigor mortis (at room temperature). Comparisons of the broad compliance-frequency disk spectra with those of five synthetic polymeric materials, including a silicone rubber, are presented and suggestions for materials suitable to be used in disk prosthesis are made. Such materials must have values of both elastic compliance (J′) and viscous compliance (J″) which are close to the corresponding living disk compliances. A brief discussion of the characteristic sharp resonance dispersions or fine structure observed in the disk spectra is also presented along with suggestions for future measurements. Finally, the idea is advanced that a composite synthetic structure with a stiff, outer ring of low compliance and a very compliant inner core might most satisfactorily mimic the viscoelastic behaviour of a normal intervertebral diskin vivo.

Nonrigid Molecule Effects on the Rovibronic Energy Levels and Spectra of Phosphorous Pentafluoride

Although phosphorous pentafluoride is known from electron diffraction, infrared, and Raman data to have a D3h trigonal bipyramid equilibrium configuration, NMR data shows only one fluorine resonance. Although this is almost certainly due to a fast intramolecular rearrangement process occurring via a Berry pseudo rotation, the detailed mechanism (e.g., classical thermal rearrangement or quantum mechanical tunneling in low vibrational levels) is unknown. A theoretical study has been made of the effects of quantum mechanical tunneling on the rovibronic levels, i.e., treating phosphorous pentafluoride as a nonrigid molecule. The levels are shown to be split in a very characteristic manner. Simple results for the relative intensities of the resultant fine structure to the original rovibronic transitions have also been obtained. This predicted, characteristic fine structure could be searched for experimentally in order to further our understanding of the intramolecular rearrangement process occurring in phosphorous pentafluoride. A theoretical study on a suitable millimeter wave spectroscopic experiment shows that such an experiment is at present on the border line of accessibility. A new general method of treating nonrigid molecule energy levels is illustrated by this application to the specific case of phosphorous pentafluoride.

Neural and Glial Secretion in the Spinal Cord of the Lamprey (Lampetra planeri)

In the spinal cord of Lampetra planeri neurosecretion and glial secretion could be demonstrated with histochemical methods and the aid of the electron microscope. Neurosecretion is present in either all or some “dorsal cells” which are scattered along the whole spinal cord. These cells have the characteristic fine structure of highly active secretory neurons. The cells produce three types of secretory material. One not bound to vesicles in form of a finely granulated substance, a second one in spherical, uniformely electron-dense elementary vesicles with a diameter of 100–140 nm, and a third one in vesicles of the monoamine type. In the most caudal part of the spinal cord glial secretion is present. Groups of glial cells produce a fine, granulated material and release it into the adjacent intercellular space. From there the material extends into other intercellular spaces of the spinal cord. We are of the opinion that the “dorsal cells” are forerunners of the cells of Dahlgren in higher vertebrates and that the neurosecretion and glial secretion in the spinal cord of lampreys demonstrate very primitive conditions.

Hemoglobin Interaction: Modification of Solid Phase Composition in the Sickling Phenomenon

Direct analyses of solid phase formed by deoxygenating solutions of sickle-cell hemoglobin (Hb S) in the presence of certain other hemoglobin species show that hemoglobins A and C can participate in the filamentous fine structure characteristic of the sickling phenomenon. In contrast, fetal hemoglobin (Hb F) is nearly completely excluded.

ELECTRON MICROSCOPY FOR THE DIAGNOSIS OF CUTANIOUS VIRAL INFECTIONS

SUMMARY.— The characteristic fine structure of the viruses which infect the skin is demonstrated by several methods of specimen preparation. The older methods of negative staining with phosphotungstate and of fixation of fresh tissue with osmium followed by thin sectioning are compared with a new method of electron microscopy of old tissue sections originally prepared for light microscopy. By using the appropriate technique, a clinical diagnosis can be confirmed in an electron microscopy laboratory using either vesicle fluid, fresh tissue, crusts, or even old formalin-fixed, paraffin-embedded, stained histological sections. Representative electron micrographs of the pox viruses: molluscum contagiosum, vaccinia, smallpox, milkers' nodules; of herpes simplex; of human papilloma; and of the possible virus of lupus erythematosus are presented.

Properties and structures of films drawn from polyethylene single‐crystal mats

AbstractThe properties and structures of polyethylene films drawn from mats of single crystals were investigated in comparison with films drawn from bulk polymer. The most important result obtained is that the structural reorganization stimulated by mechanical stress and annealing occurs with much greater difficulty in the mat‐drawn film. The chief mechanical characteristics of the film are a very low extensibility and a very high modulus. Structural characteristics, such as the double‐orientation of the crystalline region and the morphology of the crystals, do suffer no substantial changes during annealing at high temperatures. This stability of the structure can be related to the characteristic fine structure of the mat‐drawn film in which there are a much larger number of tie chains, connecting neighboring crystals, than in the bulk‐drawn specimen. Relaxation of the amorphous region and a notable increase in long spacing take place in the mat‐drawn sample as in ordinary bulk‐drawn samples. However, the morphological changes of the crystals accompanied by the folding back of chains seem to take place with great difficulty during annealing even in the vicinity of the melting point.

Electron microscope studies of macrogametes and fertilization in Eimeria bovis.

Mature macrogametes of Eimeria bovis in the mucosa of the colon of calves killed 17 days after inoculation had a characteristic fine structure. Numerous osmiophilic wall-forming bodies of type I were located peripherally in the macrogamete, whereas the wall-forming bodies of type II were relatively large and located more centrally. Numerous polysaccharide bodies and lipid inclusions were also present. The parasitophorous vacuole, when present, was narrow and had electron-pale contents. The host cell cytoplasm was vacuolated; in some specimens the host cell appeared to have disintegrated. A microgamete was observed within a vacuole in the cytoplasm of a macrogamete from a calf killed 19 days after inoculation. This microgamete had two flagella and a homogeneous osmiophilic nucleus. The wall-forming bodies of type I and type II were altered in this macrogamete as compared with those of mature macrogametes, indicating that oocyst wall formation had begun. Many microgametes were observed in the cytoplasm of the host cell as well as in the parasitophorous vacuole of the macrogamete.

The fine structure of the axial organ of the feather star Nemaster rubiginosa (echinodermata: crinoidea)

The fine structure of all the constituent cell type of the crinoid axial organ is described (coelomic epithelial cells, muscles, free cells, gland cells and neurons) ; also described is the fine structure of the extracellular haemal fluid. The gland cells of the glandular tubules of the axial organ have the characteristic fine structure of protein exporting cells and may produce granular and filamentous components of the haemal fluid. The neurons (perikarya and axons) of the axial organ may possibly be neurosecretory, since they are filled with electron-dense granules. Homologies between the axial organs of different echinoderm classes are discussed.

Ultrastructural features of extramammary Paget's disease.

In the epidermis of a case of Paget's disease of the vulva two atypical cell variants (type I cells or clear cells and type II cells or dark cells) have been shown, which have the characteristic fine structure of glandular cells. The same finding has been noticed in Paget's disease of the nipple.

Reversible and Irreversible Sickling: a Distinction by Electron Microscopy

Abstract Fixatives having either oxidizing or reducing properties were tested in a technic designed to preserve morphologic characteristics of circulating Hb SS erythrocytes. Red cells with cytoplasmic filaments presumably composed of deoxygenated Hb S were found at random by electron microscopy in all preparations. Glutaraldehyde provided the best preservation and was used in subsequent experiments. Venous blood from Hb SS patients was separated by ultracentrifugation into fractions rich in ISC and rich in non-ISC. The two types of erythrocytes, either oxygenated or deoxygenated, were morphologically distinct; and the aberrant appearance of ISC membranes suggested structural damage. Deoxygenation of non-ISC was associated with loose arrangements of filaments demonstrating a tendency to lie parallel within cell protuberances and in cells’ long axes. Cytoplasm of ISC, devoid of detail when oxygenated, acquired a characteristic filamentous fine structure when deoxygenated: the filament pattern implied either i) a molecular organization of hemoglobin within oxygenated ISC invisible in the electron microscope, or ii) filament formation along paths of least resistance in these irreversibly deformed cells. Behavior of ISC in a magnetic field favored the latter explanation. These observations are consistent with at least two sequences possibly associated with reversible sickling: filament formation leads to cell distortion, or cell distortion dictates filament arrangement. Both sequences may operate, each augmenting the other. In contrast, permanent deformation of cell shape known as irreversible sickling appears to be the morphologic contribution of membranes presumably damaged during periods of prolonged sequestration.

Microwave-optical double quantum studies of short-lived triplet systems

An optical method for the detection of the e.p.r. of phosphorescent systems is described and applied to the study of triplet excitations in crystalline benzophenone at 4.2K. The signals observed can be grouped into two categories which are very different in structure, saturation behaviour, and relaxation time. The signals in one of these categories are shown to arise from triplet excitons. It requires more than one characteristic time to describe the propagation of these excitions; the characteristic times are in the neighbourhood of 1.5 × 10–11 s and 2 × 10–10 s. Magneto-optical activity characteristic and magnetic fine structure principal values of the excitons are presented.

Fine structure and radiation resistance in Acinetobacter: studies on a resistant strain.

ABSTRACT An electron-microscope study of thin sections and negatively stained preparations of intact cells and isolated cell walls of a bacterium which is moderately resistant to ionizing radiation, Acinetobacter strain 199 A, showed that it is similar to other Gram-negative bacteria except for its mode of division and for the fine structure of some of the surface layers. During division the cells form a fairly thick septum similar to those observed in Gram-positive bacteria. An examination of the appearance and chemical composition of isolated cell walls before and after treatment with enzymes, detergents and lipid solvents revealed that three layers, each with a characteristic fine structure, are present in the cell wall: (1) an outer membrane with an array of peg-like subunits; (2) a layer of wrinkled material which is digested by proteolytic enzymes; and (3) a smooth, rigid layer, which contains the mucopeptide components of the cell wall. These observations are compared with the results of other workers for various Gram-negative bacteria. From comparisons with the structure of more radiation-sensitive strains of Acinetobacter, it appears that layer (2) may be associated with the radiation resistance of the organism.

The fine structure of Micrococcus radiodurans.

The fine structure of the radiation-resistant bacterium, Micrococcus radiodurans, isolated by Anderson, was studied by electron microscopy of intact and disrupted cells using thin sectioning and negative staining techniques. The cytoplasm and nuclear structures are normal, but the cell wall and sheath are more complex than any so far described for a bacterium. The surface consists of four distinct layers, each having a characteristic fine structure, one of which has been tentatively identified as that responsible for maintaining the rigidity of the cells. Striations with a periodicity of 175 to 200 A are visible in thin sections of this layer, and a pseudo-hexagonal array of dark “holes” is seen in surface view of negatively-stained fragments. It is concluded that this layer is the main structural element of the cell wall of M. radiodurans. The other three layers of the surface have not been clearly located in thin sections; one of these layers has a well-defined pattern of hexagonally arranged units similar to that observed in Spirillum serpens by Murray but with different dimensions.

Observations on healing tissue: A combined light and electron microscopic investigation

1. The process of healing in the rabbit ear chamber has been investigated in detail by correlating light microscopy, mainlyin vivo, and electron microscopy. 2. During healing new vessels are formed from existing vessels by a process of sprouting and anastomosis, with subsequent remodelling of the loops so formed. 3. The fundamental process in the formation of vessels by sprouting is the mitotic division of existing endothelium, during which it retains its characteristic properties. 4. Blood vessel sprouts are composed of strands of tightly apposed cells formed in continuity with the walls of existing vessels. The subsequent canalization of such strands takes place extra-cellularly by a series of events largely as described by Billroth (1856). 5. The endothelium of recently formed vessels has a fine structure which distinguishes it clearly from that of more mature vessels. Certain features of this structure are compatible with a secretory activity by the endothelium during the formation of new vessels. 6. Evidence was obtained that in the course of differentiation of recently formed vessels fibroblast-like cells are incorporated into vessel walls to become adventitial cells, and that adventitial cells may undergo conversion to vascular smooth muscle cells. 7. Lymphatic endothelium exhibits properties during regeneration that confirm the specificity of this form of endothelium. 8. Cells with the characteristic fine structure of fibroblasts were frequently found in mitosis. The fibroblasts in the regions of active fibrogenesis had a highly developed cisternal form of endoplasmic reticulum. Vesicles and corresponding caveolae identifiable in such fibroblasts may provide a communication between the endoplasmic reticulum and the sites of fibrogenesis at the external surfaces of the cells. 9. Cells sharing characteristic features of fine structure formed a series which grouped together the monocyte, macrophage and foreign body giant cell. 10. Highly fibrillary intracytoplasmic tracts were found in both fibroblasts and macrophages. These tracts were equated with the fibroglial fibres of light microscopy. 11. ‘ Clear spaces ’ in advance of the growing fringe of blood vessels were temporary structures lined by a pavement of mesothelium-like cells. 12. No evidence was found of the formation of primitive mesenchymal tissue during healing in the mammal.

332. The nitrous acid–tributyl phosphate complex

Tributyl phosphate extracts nitrous acid almost quantitatively from aqueous solutions./The spectrum, from 320 to 400 m mu , shows the enhanced fine structure characteristic of molecular nitrous acid and of alkyl nitrites. Distribution data indicate a 1: 1 complex, STABu/sub 3/PO/sub 4/,HO NO!, and infrared spectra that the hydrogen-bonding to the phosphoryl-oxygen atom modifies the bonding in nitrous acid toward an ionic structure. (auth)

Studies on the cornea. II. The fine structure of Descement's membrane.

Descemet's membrane, previously thought to be "structureless," has been found to be characterized by a fine structure of great regularity. Sections perpendicular to the plane of the membrane surface appeared to be cross-striated, with narrow dark bands separated by wide light bands traversed by fine filaments. Tangential sections showed a two-dimensional array of dark nodes and thin internodal filaments which connected each node with the six others around it to form a hexagonal figure. The average distance between nodes, and between the dark bands in transverse sections, was about 1070 A; the width of the nodes was about 270 A; and the width of the connecting filaments was less than 100 A. This pattern has been found in all species of Descemet's membrane so far examined, although it appeared to be better developed in some forms than in others. So far as is known, it has not been observed in any other type of tissue. The differentiation of Descemet's membrane has been followed in the chick embryo. It appeared late and developed slowly but showed the characteristic fine structure from the time it could be clearly identified. The evidence for placing Descemet's membrane in the collagen class of proteins is strongly supplemented by the results obtained from x-ray diffraction examination by Rougvie and Bear.