bluuebunny/crossref_metadata_2025 huggingface dataset:
Exogeneous factors are not necessary in attachment, spreading and polarization of hela cells
Authors: Liebrich W.
Published: June 2020

HeLa cells were grown for 2-3 days in EAGLE'S minimum essential medium with 10% calf serum (S-MEM; Seromed, München) and then incubated for 24 hours in serum free medium (MEM). After detaching the cells with a solution of 0. 14 % EDTA and 0. 07 % trypsin (Difco,
1 : 250) they were suspended in various solutions (S-MEM = control, MEM, buffered salt solutions with or without Me++ions, 0. 9 % NaCl solution) and allowed to settle on glass tube slips (Leighton-tubes). After 5, 10, 15, 20, 25, 30, 1 45, 60 minutes 2, 3, 4, 5 hours cells were prepared for scanning electron microscopy as described by Paweletz and Schroeter. The preparations were examined in a Jeol SEM (JSM-U3) at 25 KV without tilting.

The suspended spherical HeLa cells are able to adhere to the glass support in all solutions. The rate of attachment, however, is faster in solutions without serum than in the control. The latter is in agreement with the findings of other authors.
Ultrastructural modification of cellular interactions in cancer tumor
Authors: Dmitrieva N. P.
Published: June 2020

One of the most characteristic features of cancer cells is their ability to metastasia. It is suggested that the modifications of the structure and properties of cancer cells surfaces play the main role in this process. The present work was aimed at finding out what ultrastructural features apear in tumor in vivo which removal of individual cancer cells from the cell population can provide. For this purpose the cellular interactions in the normal human thyroid and cancer tumor of this gland electron microscopic were studied. The tissues were fixed in osmium tetroxide and were embedded in Araldite-Epon.

In normal human thyroid the most common type of intercellular contacts was represented by simple junction formed by the parallelalignment of adjacent cell membranees leaving in between an intermembranes space 15-20 nm filled with electronlucid material (Fig. 1a). Sometimes in the basal part of cells dilatations of the intercellular space 40-50 nm wide were found (Fig. 1a). Here the cell surfaces may form single short microvilli.
Electron microscopy of embryonic envelope formation by the cestode proteocephalus longicollis (zeder, 1800)(proteocephalidea)
Authors: Swiderski Z. , Subilia L.
Published: June 2020

Four main embryonic envelopes, the capsule, outer envelope, inner envelope and oncospheral membrane, are formed around the developing embryos of Proteocephalus longicollis, a parasite of fishes.

The capsule, formed from shell-globule material of vitelline cells, is the first embryonic envelope which encloses the fertilized oocyte and a single vitelline cell (Fig. 1) when they pass through the ootype and enter the uterus. At this initial stage of embryogenesis, the capsule is formed of two closely apposed membranes (Fig. 1, inset). In more advanced stages, the capsule slightly increases its volume, and a fine-fibrillar material accumulates in the space between its two limiting membranes (Fig. 2).
Three dimensional fine structure of the capillary terminals in the red pulp of the human spleen
Authors: Suzuki Teruo , Shimizu Susumu , Hataba Yoshiaki , Kirino Yuji
Published: June 2020

Introduction In spite of the efforts of many researchers, three dimensional fine structure of the capillary terminals in the red pulp of the spleen has not been successively demonstrated up to date. By stereoscopic scanning electron microscopy of a perfusion-fixed and freeze-fractured dog spleen, we have recently demonstrated that the terminals of the cordal capillaries are obviously open in the cordal labyrinth.

Material and Methods In the human spleen, however, applications of the same method only was not necessarily successful to obtain unquestionable informations on their three dimensional structure, since it is very difficult to flush out blood cells thoroughly from the cordal labyrinth at the time of the perfusion fixation. In the present study, a synthetical observation of the capillary terminals in the red pulp of the normal human spleen was undertaken by three ways of; 1) transmission electron microscopy of ultrathin sections (TEM), 2) scanning electron microscopy of freeze-fractured tissue (FF-SEM), and 3) scanning electron microscopy of serial sections from which the embedding medium was removed (SS-SEM).
An electron microscopic study of the intra-myocardial lesions in cases of acute myocardial infarction
Authors: Ono Masahiro , Aihara Kaoru , Yajima Gompachi
Published: June 2020

The pathogenesis of the arteriosclerosis in the acute myocardial infarction is the matter of the extensive survey with the transmission electron microscopy in experimental and clinical materials. In the previous communication,the authors have clarified that the two types of the coronary vascular changes could exist. The first category is the case in which we had failed to observe no occlusive changes of the coronary vessels which eventually form the myocardial infarction. The next category is the case in which occlusive -thrombotic changes are observed in which the myocardial infarction will be taken placed as the final event. The authors incline to designate the former category as the non-occlusive-non thrombotic lesions. The most important findings in both cases are the “mechanical destruction of the vascular wall and imbibition of the serous component” which are most frequently observed at the proximal portion of the coronary main trunk.
Glomerular permeability in the fetal rabbit
Authors: Monica M. L. , Zimny M. L. , McClugage S. G.
Published: June 2020

The purpose of this study was to determine fetal age differences in glomerular permeability using a graded series of dextrans (Pharmacia, Inc., Uppsala, Sweden). The dextran fractions were highly purified and consisted of the following sizes: T-10, T-40 and T-110 (10,000, 40,000 and 110,000 M.W. respectively). The foundation for this study was the work of Caulfield and Farquhar, who showed, using a graded series of dextrans, that the basement membrane was the definitive barrier to permeability.

A total of 120 fetuses of pregnant New Zealand white rabbits at the following periods of gestation: 20, 22, 24, 28 days and one day old neonates were utilized. Accurate determination of each fetus' developmental stage was based on weight and crown-rump measurements made at the time of sacrifice. Pregnant rabbits were anesthesized with 20% urethane (ethyl carbamate) and a longitudinal incision was made in the shaved lower abdomen. A small incision was placed in the exposed uterus which penetrated the amniotic sac allowing for removal of the fetus. Viability of the fetus was essential and each fetus remained attached to the placenta throughout the course of dextran injection.
Immunoferritin localization of amylase and chymotrypsinogen in stimulated and unstimulated rat exocrine pancreatic cells
Authors: Geuze J. J. , Slot J. W.
Published: June 2020

The precise localization of secretory proteins in exocrine pancreatic cells has not yet been elucidated. Especially the role of the Golgi complex in protein processing remains a matter of controversy. Based on morphological and autoradiographical work with the frog pancreas, we described proteins moving from the peripheral elements at the cis (immature) side of the Golgi complex across the stack of Golgi cisternae towards the condensing vacuoles at the trans (mature) side of the Golgi complex. Jamieson and Palade described a similar pathway in the stimulated Guinae pig pancreas, but suggested that in unstimulated cells the Golgi cisternae are bypassed and that vesicles carry proteins directly from the RER to the condensing vacuoles. Novikoff et al. postulate from their study on pancreatic cells of 4 mammalian species including Guinea pig and rat that condensing vacuoles can originate directly from specialized regions of the ER (so-called GERL) at the trans side of the Golgi complex. This makes the role of the peripheral elements and the Golgi cisternae in protein processing even more doubtful.
Ultrastructure of isolated and cultured rat pancreatic ducts
Authors: Ruby J. R. , Githens S. , Holmquist D. R. G.
Published: June 2020

Carcinoma of the exocrine pancreas in humans will often appear morphologically like duct epithelial tissue. It is not known, however, if such duct cell adenocarcinoma arise from duct cells directly, or from the neoplastic transformation of another pancreatic cell type such as the acinar cells. In either case, a better understanding of this type of cancer is necessary. To date, most of the information concerning pancreatic duct epithelium has been based primarily on studies of the intact pancreas. Thus, this investigation was an attempt to isolate rat pancreatic ducts so that they could be studied ultrastructurally and biochemically before and after culture. The ultimate intent is to expose the cultured ducts to carcinogens, in order to determine which carcinogens have an effect on duct tissue, and the nature of such effects.

Juvenile rat pancreases were digested with collagenase and duct fragments were separated from acinar tissue by flotation through a Ficoll gradient or by filtration through stainless steel sieves.
The ultrastructure of rat jejunal enterocytes after colchicine application
Authors: Pavelka M. , Stockinger L.
Published: June 2020

In jejunal enterocytes microtubules (mts) have been supposed to be involved in mechanisms of lipid particle transport. To elucidate the role of mts in this context detailed ultrastructural studies of rat jejunal enterocytes after application of the microtubule-inhibiting substance colchicine have been performed.

Material and Methods:Female Sprague-Dawley rats having been fasted for 24 hours received 0. 5 mg colchicine per 100 g body weight dissolved in 1. 0 ml of 0. 9% NaCl (experimental group) or 1. 0 ml of 0. 9% NaCl (control group) intraperitoneally. Segments of the upper jejunum were excised 11/2,23, 4 and 6 hours later and prepared for electron- microscopical observation (Fixation:2. 5% sodium phosphate buffered glutaraldehyde, pH 7. 2; Postfixation: 1% veronalacetate buffered OsO4; Embedding in Epon; Staining with alcoholic uranylacetate and alkaline lead citrate).

Results:The ultrastructural alterations after colchicine application concern predominantly mts and Golgi apparatus and are apparent already 11/2 hours after colchicine application.
The fine structure of the camel corpus luteum of early pregnancy and after parturition
Authors: Nayak R. K.
Published: June 2020

The structure and function of the corpus luteum has been studied intensively, yet many of the factors and events in formation, maintenance, function and regression of this endocrine gland remain unclear. Christensen and Gillim reviewed the literature dealing with steroid-secreting cells including lutein cells. They clearly documented the role of smooth endoplasmic reticulum in steroid biosynthesis. The fine structure of the corpus luteum has been described in a variety of animals including rat, mouse, hamster, guinea pig, rabbit, pig, cow, sheep, deer, dog, racoon, mink, badger, lemur, armadillo and man. Recently, Enders reviewed in detail the results obtained on the cytology of corpus luteum granulosa lutein cells of early pregnancy.

Novoa has recently attempted to correlate some reproductive phenomena in Camelidae with those of other domestic animals. Since the literature is essentially devoid of information on electron microscopy of the camel corpus luteum and since fresh camel corpus luteum specimens were obtained in excellent condition, a critical study was undertaken to provide definitive information on the structure and function of the corpus luteum during early stages of pregnancy and after parturition in the one-humped camel, Camelus dromedarius.
Osmiophilic granules releasing from the surface of human decidual cells
Authors: Hirasawa Takeshi , Hashimoto Masayoshi
Published: June 2020

The purpose of the present paper is to clarify the process of decidual change of endometrial stromal cells during pregnancy and especially to give a detailed report on the osmiophilic granules releasing from the surface of the decidual cells.

The materials used in the present study were the decidua obtained at therapeutic abortions of 6-12 weeks of gastation.

The tissues were fixed in 0. 1M-phosphate buffered osmium tetraoxide at pH7. 2, dehydrated in graded concentration of ethanol, and embedded in Epon 812. Medium-thin sections were stained with toluidine blue for purposes of area identification and selection for ultrathin sections. The ultrathin sections were stained with uranyl acetate and lead citrate.

The endometrial stromal cells of the decidua parietalis and the marginal area of the portion on which the ovum rests:

The endometrial stromal cells of this site are characterized by moderately developed Golgi area, numerous cisternae of r-ER containing fine fibrillar substances, small and rod-shaped mitochondria with undefined cristae and external lamina.
Transport of glial smooth endoplasmic reticulum acid phosphatase into damaged axons: possible role of microtubules
Authors: Griffiths Gareth W.
Published: June 2020

Earlier observations indicated that cutting the photoreceptor (R) cell perikarya of the flies Musca domestica and Calliphora erythrocephala in the retina led to clear cut degenerative changes, occurring within minutes, in the R axons in the optic neuropiles. Biochemical assays of the lysosomal marker enzyme acid phosphatase (AcPase) in the optic ganglia at various times following the lesion showed a highly significant increase in activity concomitant with the morphological changes. Cytochemical assay of AcPase activity using the Gomori method indicated that the increase in AcPase activity was exclusively associated with one specific glial cell type - the satellite glia (SG). These cells are contiguous with the R cell axons only in the distal lamina, directly beneath the basement membrane of the retina. Reaction product indicating AcPase activity appeared sequentially in the SG cytoplasm (2-4 mins), extracellularly between glial and axon membranes (3-5 mins) and then in the axon cytoplasm (>4 mins).
Relationship between golgi apparatus and axonal reticulum in sympathetic ganglion cells
Authors: Quatacker J. , De Potter W.
Published: June 2020

Mucopolysaccharides have been demonstrated biochemically in catecholamine-containing subcellular particles in different rat, cat and ox tissues. As catecholamine-containing granules seem to arise from the Golgi apparatus and some also from the axoplasmic reticulum we examined wether carbohydrate macromolecules could be detected in the small and large dense core vesicles and in structures related to them. To this purpose superior cervical ganglia and irises from rabbit and cat and coeliac ganglia and their axons from dog were subjected to the chromaffin reaction to show the distribution of catecholamine-containing granules. Some material was also embedded in glycolmethacrylate (GMA) and stained with phosphotungstic acid (PTA) at low pH for the detection of carbohydrate macromolecules.

The chromaffin reaction in the perikarya reveals mainly large dense core vesicles, but in the axon hillock, the axons and the terminals, the small dense core vesicles are more prominent. In the axons the small granules are sometimes seen inside a reticular network (fig. 1).
Electron microscopic studies on the postnatal growth of mouse iridocorneal angle
Authors: Yoshida K. , Murata F. , Ohno S. , Nagata T.
Published: June 2020

The iridocorneal angle(ICA) occupies an important position in the eye from the viewpoint of the aqueous outflow pathway. There are several studies on the iridocorneal angle formation of the mammalian eyes, such as the rat, monkey and man. However, there is no paper available on that of the mouse. The purpose of this study is to report the developmental process of the iridocorneal angle formation in the mouse eye.

Albino mice of various ages from newborn to adult were used in this study. The ages of mice were 3, 5, 7, 9, 10, 11, 14 days old, 1, 6 and 12 months old. At least three individual animals were studied at each developing stage. After decapitation, the eyes were quickly enucleated, and were prefixed in 2. 5% glutaraldehyde in 0. 1 M phosphate buffer (pH 7. 4) for three hours. They were then measured at their diameters before postfixation in 1% osmium tetroxide for two hours, dehydrated in a graded series of ethanol and embedded in Epon with a flat embedding mold to ensure their direction. Ultrathin sections were cut with an LKB Ultrotome, placed on the collodion coated grids and stained with uranyl acetate and lead citrate before observation with a Hitachi HS-9 electron microscope.
Membranous alterations in the cytoplasm and nucleus in a primitive neuroectodermal tumor of the brain
Authors: Sun C. N. , Araoz C. , White H. J.
Published: June 2020

The ultrastructure of a cerebral primitive neuroectodermal tumor has been reported previously. In the present case, we will present some unusual previously unreported membranous structures and alterations in the cytoplasm and nucleus of the tumor cells.

Specimens were cut into small pieces about 1 mm3 and immediately fixed in 4% glutaraldehyde in phosphate buffer for two hours, then post-fixed in 1% buffered osmium tetroxide for one hour. After dehydration, tissues were embedded in Epon 812. Thin sections were stained with uranyl acetate and lead citrate.

In the cytoplasm of the tumor cells, we found paired cisternae (Fig. 1) and annulate lamellae (Fig. 2) noting that the annulate lamellae were sometimes associated with the outer nuclear envelope (Fig. 3). These membranous structures have been reported in other tumor cells. In our case, mitochondrial to nuclear envelope fusions were often noted (Fig. 4). Although this phenomenon was reported in an oncocytoma, their frequency in the present study is quite striking.
Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro
Authors: Garcia Raul I. , Flynn Evelyn A. , Szabo George
Published: June 2020

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.
New methods to simultaneously localize proteoglycan by LM and EM
Authors: Shepard Nona
Published: June 2020

Proteoglycan is a major component ofa cartilage and up to 70% can be lost during routine processing unless special measures are taken. With this in mind and the fact that proteoglycan loss and or alteration is primary in most pathological conditions of articular cartilage, full retention is, therefore, essential to validate the interpreting of electron micrographs.

The cationic dyes, Safranin 0 and Toluidine Blue 0, seemed like likely candidates as their chemical interaction with proteoglycan has been well documented by Rosenberg. Both dyes bind stoichlometrically to polyanions; one molecule of dye to each negatively charged chondroitin 6 - sulfate or keratan sulphate molecule. Szirmal has reported that cationic dyes bind proteoglycan of fresh sectioned tissue. Therefore, following Insitu fixation with Safaranin 0 or Toluidinz Blue 0, thz resulting Image would be a quantitative example of proteoglycan localization and if present in sufficent mass would scatter electrons. Ruthenium red is widely used for E. M., but we found it of little value as an L. M. stain
HVEM of the human immunodeficiency virus
Authors: Song M. J. , Pudney J.
Published: June 2020

The human immunodeficiency virus (HIV-1), the causative agent of the acquired immunodeficiency syndrome, is a retrovirus. HIV-1 infects host cells by fusing with the plasma membrane and injecting viral RNA into the cytoplasm. Viral RNA induces the synthesis of viral DNA that is integrated into the host genome. Viral progeny are secreted by budding from the plasma membrane. Only two periods in the life cycle of the virus are amenable for examining morphological interactions between HIV-1 and host cells: during infection, before the virus disassembles prior to viral DNA production, and morphogenesis of HIV-1, as structural components are assembled at the host plasma membrane. Although these periods are critical for the success of HIV-1 they have not been widely investigated at the electron-microscope level. To address this we have used high-voltage electron microscopy (HVEM) to analyze the spatial and morphological associations between HIV-1 and host cells during infection and morphogenesis.
Microstnictural characterization and x-ray microanalysis of human bone by SEM and image analysis
Authors: Armand C. , Dorlot J.M. , Yahia H. , Meunier A.
Published: June 2020

Introduction

The purpose of this work was to investigate a possible correlation between mechanical properties, microstructure and mineral content of human bone tissue. This study will improve our knowledge of bone mechanics and bone remodelling. Meunier et al. developed a new technique to obtain local mechanical properties by scanning acoustic microscopy (SAM). A good correlation was obtained between the average acoustic impedance and the elastic stiffness patterns of bone. We will present results concerning the evaluation of the microstructure and the mineral content of human tibiae and femora.

Materials and Methods

In order to assess whether correlation exists or not between morphology, mineral content and the acoustic impedance, we worked on the same specimens as Meunier; 20 fresh right paired human tibiae and femora (6 females and 14 males) retrieved at necropsy; age ranged from 48 to 92 years and weight from 40 to 90 kg.

Using a low-speed diamond saw, samples of 100-120 μm thickness were cut, polished and dehydrated stepwise in ethanol (60-100%). The specimens were coated with carbon to eliminate charging effects and examined with JEOL JSM 840 scanning electron microscope equipped with a LINK LZ4 for x-ray spectrometer and with backscattered (BS) electron detector. Micrographs with BS electrons were taken at 20KV. BS images are transferred to an IBAS2 image analyser to quantify the microstructure by difference of grey levels. X-ray analyses are made at 15KV to obtain mineral content, mainly Ca and P. We performed x-ray analyses on areas of .45mm2 (covering about 30 osteons) on different zones on each sample (as defined on figure 1) . Synthetic hydroxyapatite was used as a standard in order to quantify the mineral content for each analysis. We studied the variation of the mineral content at different levels expressed in % of cortical thickness from the perioste (0%) to the endoste (100%).

Results and Discussion

The main features investigated were Microstructural characteristics (porosity (%), osteon density, Haversian canal areas) and Mineral content (Ca and P amount expressed in % of HAp, Ca/P ratio computed from x-ray net intensity, global amount of mineral present in the bone matrix). We had investigated differences between tibiae and femora and the evolution between successive levels within the same bone category. Figures 2a,b and 3a,b show typical results of the two categories studied for Haversian canal and osteon density, mineral content and Ca/P ratio respectively. In term of microstructural parameters, femur and tibia exhibit significant differences mostly in the central and endosteal part. This founding has to be related with results found using acoustic measurements in which the longitudinal elastic stiffness (C33) was significantly different between tibia and femur. Regarding the mineral content, no significant difference has been found between tibia and femur. However, the Ca/P ratio is significantly different between tibia and femur.
High conductivity amorphous Ti88Si12 substrates for low-temperature Electron Microscopy
Authors: Rader R.S. , Lamvik M.K.
Published: June 2020

To avoid problems with charging, microscopists usually use conductive substrates and coatings on nonconductive organic specimens. But when specimens are observed at low temperatures, some previously adequate substrates, like carbon films, become poor electrical conductors. Titanium films have high conductivity at low temperature, but the microcrystalline structure of the films can disturb high magnification images (fig. 1a). For that reason, we have looked for amorphous high conductivity films.

Amorphous titanium-silicon alloys have been extensively studied as low-resistivity materials for connecting integrated circuits. We chose to examine a Ti88Si12 alloy due to our previous familiarity with titanium films, the excellent glass forming ability of this and similar late transition metal-metalloid alloys, and the ease of depositing the material in an evaporation system that could commonly be found in microscopy labs.
New observations of colloid cysts of the third ventricle: An ultrastructural study of the lining epithelium and the wall
Authors: Ho Khang-Loon , Garcia Julio H.
Published: June 2020

Colloid cysts of the third ventricle represent one of the variety of the epithelial-lined cysts of the neuraxis. Their histogenesis remains unsettled. Ultrastructural and immunohistochemical analyses have suggested the following possible origins: (a) neuroectoderm, including paraphysis, ependyma, choroid plexus, and tela choroidea and (b) endoderm, including respiratory and enteric epithelium.

This report describes the ultrastructure of the lining epithelium and the wall of four cases of colloid cyst. Six distinct cell types were recognized in the epithelium (Fig.1,2): (1) ciliated cells with various types of ciliary abnormalities, (2) non-ciliated cells with microvilli coated with granulo-fibrillary material, (3) goblet cells showing discharge of secretory granules, (4) basal cells with prominent tonofilaments, (5) basal-located cells with elongated cell bodies parallel to the basement membrane and electron-lucent cytoplasm containing sparse, membrane-bound dense core granules (150-250 nm) and (6) small undifferentiated cells with scanty organelles.
Processing of human melanoma cells for correlative TEM, LVSEM, and LM
Authors: Malecki Marek , Victor Small J. , Pawley James
Published: June 2020

The relative roles of adhesion and locomotion in malignancy have yet to be clearly established. In a tumor, subpopulations of cells may be recognized according to their capacity to invade neighbouring tissue,or to enter the blood stream and metastasize. The mechanisms of adhesion and locomotion are themselves tightly linked to the cytoskeletal apparatus and cell surface topology, including expression of integrin receptors. In our studies on melanomas with Fluorescent Microscopy (FM) and Cell Sorter(FACS), we noticed that cells in cultures derived from metastases had more numerous actin bundles, then cells from primary foci. Following this track, we attempted to develop technology allowing to compare ultrastructure of these cells using correlative Transmission Electron Microscopy(TEM) and Low Voltage Scanning Electron Microscopy(LVSEM).
Quantification of ultrastructural damage in human skeletal muscle
Authors: Manfredi T. G. , Ding W. , Evans W. J. , Fielding R. A. , Cannon J. G. , Lee H. Y. , Verdon S. L.
Published: June 2020

Qualitative microscopic analysis of muscle architecture provides information about cellular markers of muscle fiber disruption in myopathic, aging, and experimentally damaged muscle. However, this approach does not provide sensitive information regarding the extent of muscle damage and has serious limitations when research protocols address tissue remodeling. The purpose of this study was to quantitatively assess the extent of muscle damage in young and older adults before and after exercise-induced damage. The older adults in this study had lower aerobic capacities and muscle mass than their younger counterparts, suggesting greater vulnerability toward muscle damage produced by physiologic stress.

Five young males, ages 20 to 29 years and five older males, age 60 to 75 years had percutaneous needle biopsies taken from the vastis lateralis muscle before and after (N=9) exercise consisting of reverse cycling or downhill treadmill running at a prescribed physiologic effort. Muscle samples were prefixed in 3.0% gluteraldehyde in cacodylate buffer and post-fixed in VL OSO4. This was followed by routine procedures for TEM.
Characterization of microtubules by dark-field STEM and replication
Authors: Andrews S.B. , Leapman R.D. , Gallant P.E. , Reese T.S.
Published: June 2020

As part of a study on protein interactions involved in microtubule (MT)-based transport, we used the VG HB501 field-emission STEM to obtain low-dose dark-field mass maps of isolated, taxol-stabilized MTs and correlated these micrographs with detailed stereo images from replicas of the same MTs. This approach promises to be useful for determining how protein motors interact with MTs. MTs prepared from bovine and squid brain tubulin were purified and free from microtubule-associated proteins (MAPs). These MTs (0.1-1 mg/ml tubulin) were adsorbed to 3-nm evaporated carbon films supported over Formvar nets on 600-m copper grids. Following adsorption, the grids were washed twice in buffer and then in either distilled water or in isotonic or hypotonic ammonium acetate, blotted, and plunge-frozen in ethane/propane cryogen(ca.-185 C). After cryotransfer into the STEM, specimens were freeze-dried and recooled toca.-160 C for low-dose (<3000 e/nm2) dark-field mapping. The molecular weights per unit length of MT were determined relative to tobacco mosaic virus standards from elastic scattering intensities. Parallel grids were freeze-dried and rotary shadowed with Pt/C at 14°.
Confocal laser scanning fluorescence microscopy of brain microvessels: Method and preliminary results
Authors: Ghoneim Shams , Baumbach Gary
Published: June 2020

Chronic Hypertension alters both mechanical as well as compositional characteristics of cerebral blood vessels. We have previously determined that pial arterioles consist of two major cellular components : endothelium and smooth muscle. Smooth muscle cells are the predominant component in the arteriolar wall. The consensus of data published on the shape and dimension of vascular smooth muscle cells (VSM) is that the majority of cells are spindle shaped and of similar length and width. Changes in the morphological shape and dimension of VSM cells may occur during growth, aging or pathological conditions. In a previous study we demonstrated a digestion technique for SEM to view smooth muscle cells in arteriolar walls by removing basement membrane and arachnoid tissue covering and exposing the underlying cells. The technique proved technically unreliable, difficult to reproduce and resulted in damage to smooth muscle cells. The goal of this study was to determine if confocal microscopy techniques could offer a reliable, reproducible and safe substitute to digestion techniques in the study of cerebral smooth muscle cells.
Heterotypic fibrils and stabilizing collagens in corneal development
Authors: Linsenmayer T. F. , Birk D. E. , Linsenmayer C. M. , Gordon M. K. , Marchant J. K. , Fitch J. M.
Published: June 2020

Our studies on the embryonic development of the chick cornea have recently yielded information suggesting possible roles for different types and classes of collagens. The chick cornea develops through a series of precisely controlled temporal and spatial events involving cell differentiation, migration and extracellular matrix production and assembly. Each event involves, and is possibly dictated by, dramatic changes in the major molecular components of the extracellular matrix. Corneal morphogenesis begins with the formation of the primary corneal stroma, a dense subepithelial matrix consisting of orthogonally arranged, horizontal layers of collagen fibrils. Each layer is one fibril thick. This stroma then rapidly swells and immediately thereafter is invaded by pericorneal mesenchymal cells. These cells differentiate into stromal keratocytes and synthesize the secondary, mature stroma, a structure in which each orthogonal layer is many collagen fibrils thick.
Macromolecular organization of basement membrane laminin
Authors: Yurchenco Peter D.
Published: June 2020

Laminin isoforms are major structural and cell-interacting components of basement membranes. The most extensively studied isoform of this glycoprotein (800 kDa) is murine EHS laminin which consists of three polypeptide chains (A,B1,B2) disulfide linked to form a flexible four-armed molecule which in turn is often complexed to entactin, a smaller dumbell-shaped sulfated glycoprotein. One of the functions proposed for laminin is selfassembly into a polymer that constitutes a major part of basement membrane architecture. The principal evidence for this hypothesis has derived from biochemical and structural studies of laminin polymerization in vitro. Embryonal carcinoma cells (M1536B3) grown in suspension culture will differentiate into multicellular spherules that produce basement membrane cores rich in laminin/entactin but devoid of type IV collagen, a characteristic of some basement membranes of developing tissues. We now report that these cores share the same structural/biochemical features with reconstituted laminin polymers.
Assembly of fibronectin fibrils by fibroblasts cultured within an attached collagen lattice
Authors: Tomasek J. J.
Published: June 2020

Dupuytren's disease is characterized by a contraction of the palmar fascia resulting in irreversible flexion of the affected digits. Collagen lattices provide a model system for studying the cellular mechanisms of tissue contraction. Fibroblasts cultured within an attached collagen lattice resemble the myofibroblasts present in the diseased tissue. They form bundles of actin microfilaments, assemble fibronectin fibrils and form a specialized transmembrane association (fibronexus) linking the two filament systems. In addition, fibroblasts cultured in an attached collagen lattice will develop tension which results in rapid lattice retraction upon mechanical release from the underlying substratum. In this study we examined fibronectin fibril assembly in an attached collagen lattice and the potential role these fibrils play in tension development.
Metalloproteinases mediate human cytotrophoblast invasion in vitro
Authors: Fisher Susan J. , Werb Zena , Damsky Caroline H. , Librach Clifford L.
Published: June 2020

The unique anatomy of the human placental bed is established during early pregnancy when some of the fetal chorionic villi give rise to columns of mononuclear cytotrophoblasts that penetrate the superficial portion of the uterus. Cells from these columns invade the endometrium, the superficial portions of the myometrium and the uterine arterioles. This transient tumor-like behavior, which peaks at the end of the first trimester (TM) of pregnancy, is developmentally regulated by mechanisms that are as yet unknown. Previous work from this laboratory showed that invasive first TM human cytotrophoblasts produce a number of metalloproteinases, some of which are absent or greatly reduced in later-gestation, noninvasive cells. This multi-gene proteinase family includes a uterine proteinase, interstitial collagenase, three types of stromelysin and the 72 and 92 kDa type IV collagenases. Other investigators showed that term human cytotrophoblasts produce urokinase-type plasminogen activator (u-PA), but not tissue-type PA. Thus, both families of proteinases may play a role in cytotrophoblast invasion. The purpose of this study was to determine the relative contribution of each.
A T.E.M. study of mouse mammary epithelial cell secretory differentiation cultured on collagen and Matrigel
Authors: Bentham W.N. , Rocha V.
Published: June 2020

It has been an interest of our lab to develop a mammary epethelial cell culture system that faithfully duplicates thein vivocondition of the lactating gland. Since the introduction of collagen as a matrix on which cells are cultivated other E.C.M. type matrices have been made available and are used in many cell culture techniques. We have previously demonstrated that cells cultured on collagen and Matrigel do not differentiate as they doin vivo. It seems that these cultures often produce cells that show a disruption in the secretory process. The appearance of large ribosomal studded vesicles, that specifically label with antibody to casein, suggest an interruption of both protein maturation and secretion at the E.R. to golgi transition. In this report we have examined cultures on collagen and Matrigel at relative high and low seeding densities and compared them to cells from thein vivocondition.
A study of phloem sieve element structure using electron, fluorescent, and confocal microscopy
Authors: Sjolund Richard D. , Wang Chi
Published: June 2020

Phloem sieve elements are the cells responsible for the long distance transport of nutrients, primarily sugars and amino acids, in higher plants. The translocation of nutrients in these cells, joined together to form long sieve tubes, is dependent on the development of high hydrostatic pressures (20 bars or higher). The dissection of plant tissues containing these phloem cells which is necessary for microscopic study usually results in the cutting of the sieve elements and a resultant loss of phloem contents due to the explosive release of the hydrostatic pressure. Wound-sealing mechanisms involving P-protein filaments and callose deposition in the cell walls rapidly seal off wound sites and prevent the loss of translocates, especially in Angiosperms. As a result, most electron microscope images of sieve elements obtained from plant organs reveal post-injury structure following wounding.
The regulation of mitotic progression in plant cells
Authors: Wolniak Stephen M.
Published: June 2020

Mitosis is the process responsible for the partitioning of replicated chromosomes. In virtually all eukaryotes, the synchronous separation of sister chromatids delineates the simultaneous end of metaphase and onset of anaphase, but the mechanisms signaling this event are not known. It seems reasonable to suspect that the intracellular signaling pathways responsible for passage through the metapnase/anaphase transition involve changes in the cytosolic activities of protein kinases and phosphatases as well as shifts in the cytosolic level of calcium. We have used the exquisite temporal precision in mitotic progression exhibited by stamen hair cells from the spiderwort plantTradescantia virginianain a temporal bioassay to assess when during prophase and metaphase regulatory cascades involving calcium, and protein kinases and phosphatases may be initiated in living cells.
Grass leaf stomata preparation techniques for scanning electron microscopy
Authors: Hardy Joyce Phillips , Gardner John S.
Published: June 2020

Studies on gramineous stomatal characteristics, such as stomatal density and aperture size, relate these traits to ecological concerns, e.g. drought tolerance and production. Techniques for studying stomata have been utilized in the past using light microscopy. In a comparative study of stomatal apertures, it is imperative that guard cell closure not occur and die cells retain as closely as possible their natural state at the time of collection. Two species utilized in seeding roadsides and pastures, Dactylis glomerata L. and Elymus canadensis L., were processed with four different techniques for the scanning electron microscope. Abaxial and adaxial surfaces, respectively, were examined.

Leaf tissue was harvested from clonal greenhouse-grown plants and separated into four groups. One was air dried under ambient conditions. The second group was placed into a standard fixative. Following fixation, the samples were dehydrated through a standard series of ethanol and critical point dried. The third group was prepared the same as group 2, except the leaves were transferred to tetramethylsilane for two ten minute exchanges following ethanol dehydration.
The effect of physical environments on morphology of soil-borne wheat mosaic virus
Authors: Grayson R. L. , Mayes M. S. , Thornham K. T.
Published: June 2020

Soil-borne wheat mosaic virus (SBWMV) consist of a bi-partite single strand RNA genome separately encapsidated in a protein coat. The long rod of the virus is about 280nm in length and the short rod measures 90-138 nm. The virus is transmitted by the obligate, soil-inhabiting fungus, Polymyra graminis. The main economic hosts of SBWMV are wheat, barley and rye. The main method of control to avoid large losses has been the introduction of resistant varieties. Relatively little is known about the biology of the complex relationship between the parasite, vector, and host for a number of reasons. The occurrence of SBWMV inside of the fungus vector has not been observed using electron microscopy. One important goal is to store naturally infected tissue in a way which maintains the integrity of viruses for research during the off-season. The purpose of this study was to investigate what happens to SBWMV in naturally infected leaves and roots of wheat stored under various physical environments.
Measurements of DNA distribution changes in live cells
Authors: Palcic B. , Spadinger I.
Published: June 2020

It has long been recognized by pathologists that many diseases can be diagnosed by examination of stained cell preparations. Particularly important information is found in the cell nucleus. For example, in the diagnosis of cancerous and pre-cancerous states in cervical cells, nuclear size, shape, and distribution of DNA have been used to classify the cells. Many other examples can be found in the examination and diagnosis of malignant diseases and other abnormalities.

In experimental cell biology, one also finds numerous examples where critical information regarding cell status is found in the nuclear DNA. One of the most commonly used assays is that of determining DNA amount and/or degree of condensation in order to define cell cycle position. Effects of exposure to damaging agents such as ionizing radiation or toxic chemicals are also frequently assessed through examination of changes in the cell nucleus. Endpoints such as chromosome aberrations (breaks, translocations, etc.) and formation of micronuclei are commonly used in such assays.
Video microscopic studies of membrane dynamics
Authors: Jacobson Ken , Lee Greta , Lee Juliet
Published: June 2020

The application of several imaging technologies and photobleaching to problems in membrane dynamics will be presented. These techniques emphasize different aspects of the measurement of translational transport: (1) tracing the trajectories of individual molecules undergoing a two dimensional random walk, and (2) investigating bulk changes in the distribution of membrane components in the plane of the membrane in single, locomoting cells.

Nanovid microscopy, which uses 30-40 nm colloidal gold probes combined with video-enhanced contrast, allows investigation of random and directed movements of individual molecules in artificial membranes or in the plasma membrane of living cells. The movements of lipid molecules were followed in a supported, planar bilayer containing fluorescein-phosphatidylethanolamine (Fl-PE) labelled with 30 ran gold anti-fluorescein (anti-Fl) to validate the technique in a model system. The membrane-bound gold particles moved in random patterns which were indistinguishable from those produced by computer simulations of two dimensional random motion.
Experimental elimination of confronting cisternae in HeLa cells
Authors: Palisano J. R.
Published: June 2020

Although confronting cisternae (CC) were described in 1955, very little is known about their origin or function. CC have been observed in a variety of tumor cells and normal fetal rat, mouse, and human epithelial tissues. While some evidence suggests that CC arise from the nuclear envelope (NE) folding back on itself during prophase, the question remains why are CC not seen in all mitotic cells or in all tumor cells instead of selected tumor cells. These seemingly inconsistent observations have led investigators to suggest that the occurrence of CC is a phenomenon resulting from the cells rapid progress through mitosis. This hypothesis was tested during HeLa cell synchronization studies which enabled the investigator to control the movement of the cells through mitosis.
A new 1.4 nm gold-Fab probe
Authors: Hainfeld James F. , Fumya Frederic R. , Powell Richard D.
Published: June 2020

A major advance in high resolution EM immunoprobes has recently been achieved: The smallest gold particles easily seen directly in the TEM have been coupled to Fab fragments thus making them the smallest gold-antibody probe commercially available.

The gold particle, NanogoldTM, is 1.4 nm in diameter with a very controlled size range, ± 10% (Fig. 1). This is in sharp contrast to other small gold preparations, such as Auroprobe One (Janssen Life Sciences) which actually ranges from 1-3 nm.

The Fab conjugate (Fig. 2) has close to one gold particle per Fab fragment. This again is different from other gold-IgG probes that have 0.2-10 gold particles per IgG. Another difference is that the Nanogold-Fab conjugates are separate molecules in solution rather than the often extensive aggregation of other colloidal gold-IgG preparations. The problems of ratio of gold particles to antibody and aggregation in conventional colloidal conjugates were shown to be controllable by careful trial and error testing.
Rapid procedure developed for direct immune electron microscopy
Authors: Nunamaker C.E. , Haven T.R.
Published: June 2020

Negative contrast electron microscopy (NCEM) and direct immune electron microscopy (DIEM) are used in the detection of viruses. Although NCEM provides a simple and rapid method for detecting viruses in clinical specimens, 106 virus particles per milliliter must be present in the original specimen to be detected by transmission electron microscopy. DIEM has been found to be more sensitive than conventional NCEM by forming virus-antibody aggregates which are easily visible by TEM. While a DIEM procedure is utilized for routine diagnostic bovine coronavirus detection in clinical samples submitted to the Wyoming State Veterinary Laboratory, Laramie, WY (WSVL), time-consuming incubations and periodic salt precipitations (Fig. 2) have sometimes delayed the desired rapid turn-around time for TEM virus diagnosis. To help avoid these delays, modifications to the DIEM procedure have been made.
The aflagellate sperm of the ghost shrimp Callianassa californiensis
Authors: Zens L.G. , Smith N.R. , Lyke E.B.
Published: June 2020

Mature sperm from most animal phyla are similar to each other in morphology, consisting of an elongate body with an apical acrosome and a nucleus with condensed chromatin, a midpiece containing centrioles and mitochondria, and a long, motile flagellum supported by an axoneme. The aflagellate, non-motile sperm of decapod crustaceans (crabs, lobsters, crayfish, and shrimp) vary from this pattern. Most mature decapod sperm are spherical. The nucleus usually contains uncondensed chromatin which extends into radial processes that project from the nucleus; these processes contain microtubules. While mitochondria and centrioles are present in some mature decapod sperm, these organelles are absent or degenerate in others. Callianassa species are abundant and well known; however, the morphology of their sperm has not been studied before.