bluuebunny/crossref_metadata_2025 huggingface dataset:
Early Mitochondrial Alterations in Dog Hearts Following Three Periods of Total Aortic Occlusion of Cardiopulmonary By-pass
Authors: Partin J. S. , Partin J. C. , Benzing G.
Published: June 2020

Quantitative analysis was made of electron micrographs from the hearts of 12 dogs undergoing cardiopulmonary bypass on the Clark heart-lung machine, for 5, 20 and 30 minutes of total aortic occlusion with mild hypothermia (27 C). Mitochondrial changes similar to those found in animals made deficient in components of the electron transport chain occurred as early as 5 minutes. In the control dog hearts, mitochondrial volume fraction (Vvi) was 0.25 ± 0.01, but after 5 minutes of aortic occlusion, there was a striking increase in Vvi to 0.38 ± 0.03. This 52 % increase in volume appears to be due to orderly end-to-end fusion of adjacent mitochondria. Aortic occlusion longer than 5 minutes resulted in progressive specific mitochondrial changes; in addition, there was disruption of the tubular systems of the cell.
The Ultrastructure of Human Lung After Inhalation of Beryllium Dust
Authors: Watson John H. L. , Goodwin Jessica , Coates E. Osborne
Published: June 2020

This is a report from a continuing study of the ultrastructure of lung tissue from patients with lung disease. This patient had been engaged for one month prior to hospital admission in the sawing and cutting of beryllium metal, which had produced the dust which he inhaled. First symptoms were noticed after two weeks of exposure. Clinical diagnosis was acute beryllium pneumonitis. Three μg of beryllium per liter were detected in his urine. A lung biopsy taken at surgery showed by light microscopy a moderate degree of acute inflammatory infiltrate around the terminal bronchioles and in the interalveolar septae. Tissue from the biopsy was fixed in glutaraldehyde and embedded in Araldite for electron microscopy.
Comparison of Normal and Cystic Fibrotic Skin Fibroblasts
Authors: Korinek Josef , Robinson John P.
Published: June 2020

We have recently examined skin fibroblasts grown in tissue culture from five normal, three CF and two heterozygous individuals. The cell lines used in these experiments had been subcultured between one and ten times. Our ultrastructural observation as well as results of metachromatic staining with toluidine blue O essentially agree with those reported by Bartman et al.

Although the membranous bodies in CF cells appear to be lysosomes, to our knowledge no histochemical examination of these granules for the presence of lysosomal enzymes has been reported in skin fibroblasts from CF individuals. We examined these bodies for the presence of acid phosphatase in normal, heterozygous and homozygous skin fibroblasts. Our results indicate that the cytoplasmic granules which produce metachromatic staining with toluidine blue O were of about the same size as those structures revealing the presence of acid phosphatase in electron micrographs.
Intracellular Collagen Fibers in Cultured Human Synovium
Authors: Krey P.R. , Sherwood M.E. , Cohen A.S.
Published: June 2020

In the search for the etiologic agent in rheumatoid arthritis we have engaged in a long-range study characterizing the differences of normal and rheumatoid synovial cells. In one experiment the normal fetal synovium of six newborn infants who died of various causes shortly after birth were cultured. Pieces of synovium from the knee were removed at autopsy under sterile conditions, and 2 mm fragments grown in Leibovitz medium supplemented with 5% calf serum, 0.1mM glutamine and 500 units of penicillin G. At 4 day intervals tissues were washed with buffer, fixed in 3% glutaraldehyde in cacodylic acid, and later post-fixed with 1% osmium tetroxide. Pieces of rheumatoid synovium removed from patients undergoing synovectomies were similarly treated, cultured and fixed.
Comparison of Choriocarcinoma and Normal Placenta
Authors: Garancis John C. , Pattillo Roland A. , Hussa Robert O. , Straumfjord Jon V.
Published: June 2020

Two different cell lines (Be-Wo and Jar) of human gestational choriocarcinoma have been maintained in continuous tissue culture for a period of four and two years respectively without losing the ability to elaborate human chorionic gonadotropin (HCG). Tissue cultures, as revealed by electron microscopy, consisted of small cells with single nuclei. In some instances cell surfaces were provided with microvilli but more often the intercellular spaces were narrow and bridged by desmosomes. However, syncytium was not formed. Endoplasmic reticulum (ER) was poorly developed in both cell lines, except in some Be-Wo cells it was prominent. Golgi complex, lysosomes and numerous free ribosomes, as well as excessive cytoplasmic glycogen, were present in all cells (Fig. 1). Glycogen depletion and concomitant increase of ER were observed in many cells following a single dose of 10 ugm/ml of adrenalin added to medium (Fig. 2).
Bacterial Flagella
Authors: Koffler Henry
Published: June 2020

Movement of bacterial cells is accomplished through the action of flagella, organelles consisting of three morphologically distinct portions, a spiral tubular filament [(f)n] which constitutes over 90% of the organelle, an extracellular hook, and a basal structure, which is intimately associated with the cell surface. The spiral (f)n is constructed of polarly oriented ovoid subunits of flagellin (f) apparently arranged in a helical fashion. Flagellin is a unique protein in that it contains no or only few residues of cys/2, trp, pro, his, or tyr, and is capable of forming normal (f)n by self-assembly. In cells of Bacillus pumilus 101 (f)n contains two types of f(fA,fB) in a ratio of 7:3. Amino acid analyses and examination of the tryptic peptides from purified fA and fB indicate that both molecules are much alike. Both fA and fB are synthesized by the same cell and are located within the same flagellum, since both anti-fA and anti-fB sera, which react specifically with synthetic (fA)n or (fB)n can be seen to coat native (f)n of all cells and the entire length of each (f)n when examined electron microscopically.
Microtubule Model Systems: Cytoplasmic Transport in the Suctorian Tentacle and the Centrohelidian Axopod
Authors: Bardele C. F.
Published: June 2020

Suctorian tentacles, long slender microtubule-containing appendages, may be regarded as highly modified cytostomes. Predator-prey cell contact and subsequent temporary cell fusion are initiated by the discharge of haptocysts (Fig.1a,H) located in the knobbed end of the tentacle. The structure of the tentacle shaft allows orderly two-way traffic; osmiophilic granules (G) move centrifugally in the outer tube, while the prey's cytoplasm (PC) surrounded by the continuation of the knob's membrane (M) moves centripetally through the inner tube. The inner tube is bordered by 2 functionally different sets of microtubules. While the single microtubules reach to the lower end of the knob in both non-feeding and feeding states, only the microtubules linked in ribbons protrude into the upper end of the knob during feeding (Fig.1b). Arm-like projections are found on each of the individual microtubules of the ribbons in the knob region. Pood intake is interpreted as a “grasp-and-swallow” (rather than a suction) mechanism, in which repeated sliding back and forth of the microtubule ribbons in connection with an assumed membrane-microtubule interaction may generate the motive force.
Electron Microscopic Observations of Purified Oat Phytochrome
Authors: Stasny J. T. , Mumford F. E.
Published: June 2020

The following describes the gross morphology of purified oat phytochrome, as examined by negative staining for electron microscopy. Phytochrome, a chromoprotein important in plant photomorphogenesis, has two photoconvertible forms: PR, absorbing maximally at 664 nm and PFR at 724 nm. Although the isolation and purification of this photoreceptor has been achieved in several laboratories, its molecular dimensions have not been adequately characterized.

Phytochrome was extracted from etiolated oat seedlings and purified by a previously published method. The purified oat phytochrome was prepared for electron microscopic examination by precipitation at 50 percent saturation with ammonium sulphate, followed by centrifugation at 30,000xg for 20 minutes. The resulting pellet was dissolved in twice-distilled water to give a protein concentration of approximately 200 ug/ml and then dialyzed against 1000X its volume of distilled water for 18 hours at 4°C.
(EB) Virus: Latency and Expression in Transplanted and Cultured Human Cells
Authors: Uzman B. G. , Kasac M. M. , Saito H. , Krishan A.
Published: June 2020

In conjunction with the cultivation and transplantation of cells from human tumors by the Programs of Microbiology and Immunogenetics, virus surveillance by electron microscopy has been routinely employed. Of particular interest in this regard have been 3 cell lines cultured from lymph nodes or spleen of 2 patients with Hodgkin's disease and 1 patient with Letterer-Siwe's disease. Each of these cell lines when transplanted in Syrian hamster neonates conditioned with anti-lymphocyte serum grew as serially transplantable tumors; from such transplants of the 3 cell lines cell cultures were retrieved.

Herpes type virus particles (Figs. 1, 2, 3) were found in the primary cultures of all three lines, in frozen thawed aliquots of same, and in cultures retrieved from their tumors growing by serial transplantation in hamsters. No virus was detected in sections of 25 of the serially transplanted tumors. However, in 10 such tumors there were repeated instances of tubular arrays in the cisternae of the endoplasmic reticulum (Fig. 4). On serologic examination the herpes virus was shown to be the Epstein-Barr virus.
Microscopic Analysis of Salt and Water Transport Levels in Toad Urinary Bladder
Authors: DiBona D. R.
Published: June 2020

Several studies correlating a physiologic state with a microscopic appearance have been performed using the urinary bladder of the toad. This tissue is considered ideal for studies of transepithelial transport because of its apparent anatomic simplicity and the ease with which it lends itself to physiologic experimentation. The purpose of this report will be two-fold. First, a brief review of the kinds of studies that have been conducted will be provided; second, some examples of recent studies in structure-function relationships will be discussed.
Specialized Epithelia in the Avian Labyrinth (Its Distribution and Ultrastructure)
Authors: Ishiyama E. , Weibel J. , Myers E. N.
Published: June 2020

In recently years the distribution of the non-sensory specialized epithella in the inner ear has been interested among otologists. Increased understanding of the problem dealing with the fluid transport within the endolymph has been obtained these studied. To our knowledge, however, the distribution of the avian specialized cells in the inner ear has not been described adequately. In addition, ultrastructural characteristics of the osmiophilic(dark) cells in the avian labyrinth were not clearly demonstrated. Therefore, the specialized epithlia in the avian labyrinth should be further investigated and the nature of their function defined.

To demonstrat this, pigeois were investigated using phase and electron-microscopy. The specialized cells(dark and light cells) were distributed in the crlstae ampullaris, the tegmentum vasculosum of the lagena which is analogous to the stria vascularis in mammals, the saccule, the otolith lagena, the utricle and the crista negletica.
Ultrastructure of the Schistosome Granuloma
Authors: Mount P. M.
Published: June 2020

Adults of the digenetic trematode Schistosoma mansoni inhabit the mesenteric veins of their definitive hosts. A wide variety of mammals ranging from mice to men are susceptible to infection. Little or no pathology is associated with the adults' presence within the blood vessels. However, the majority of the eggs laid by the adults fail to pass from the host, are carried in the veins to the liver or intestinal wall, and become trapped in the tissues where they elicit a granulomatous response.

The schistosome granuloma has been found to be a manifestation of delayed hypersensitivity and as such represents an immunologically specific inflammatory response to the presence of e'ggs. Thus, this type of granuloma can be distinguished from the immunologically non-specific type of granulomas that occur around inert foreign bodies when they become trapped in tissue. It has been hypothesized that granuloma formation represents an attempt by the host to sequester and destroy antigens of low diffusibility which are released from the egg. This report describes some preliminary observations on the ultrastructure of granulomas elicited by Schistosoma mansoni eggs in the liver of experimentally infected white mice.
The External Shape of Human γ GI Immunoglobulin from Crystal Sections
Authors: Labaw L. W.
Published: June 2020

Crystals of a human γGl immunoglobulin have the external morphology of diamond shaped prisms. X-ray studies have shown them to be monoclinic, space group C2, with 2 molecules per unit cell. The unit cell dimensions are a = 194.1, b = 91.7, c = 51.6Å, 8 = 102°. The relatively large molecular weight of 151,000 and these unit cell dimensions made this a promising crystal to study in the EM.

Crystals similar to those used in the x-ray studies were fixed at 5°C for three weeks in a solution of mother liquor containing 5 x 10-5M sodium phosphate, pH 7.0, and 0.03% glutaraldehyde. They were postfixed with 1% osmium tetroxide for 15 min. and embedded in Maraglas the usual way. Sections were cut perpendicular to the three crystallographic axes. Such a section cut with its plane perpendicular to the z direction is shown in Fig. 1.

This projection of the crystal in the z direction shows periodicities in at least four different directions but these are only seen clearly by sighting obliquely along the micrograph.
Contrast and Resolution of Thick Sections of Muscle in the HVEM
Authors: Szirmae A. , Fisher R. M. , Moses Joan , Rice R. V.
Published: June 2020

An important advantage of high voltage microscopes is increased penetration due to reduced elastic and inelastic scattering. Since the “range” of even 50 kv electrons in organic material is more than 10 microns, penetration means the maximum specimen thickness which can be examined in the HVEM with sufficient resolution to reveal the microstructural feature of interest. In order to establish a relationship between specimen thickness and image resolution, sections of rabbit psoas muscle from 0.5 μm to 5 μm were examined over the full voltage range available as the striated structure is well known and resolution can be estimated reasonably well. Rabbit psoas muscle glycerinated for at least 30 days in buffered 50% glycerol was fixed in 2.5% glutaraldehyde buffered with 0.02M phosphate for 2 hours and rinsed. While in the buffer, the tissue was cut into 1-mm lengths and transferred to 1% osmium tetroxide followed by dehydration in graded acetone embedding in an Epon-Araldite mixture. The tissue sections were stained with 2% uranyl acetate 1 hr., in methanol and poststained with lead citrate for 20 min. and mounted on 200 mesh sandwich grids. Representative micrographs of muscle sections examined are shown in Fig. 1. In most cases several sections of each thickness cut at different times were examined. The thickness values plotted refer to the microtome setting but other methods of estimating thickness indicated that they are approximately correct. The dashed lines are drawn through micrographs of specimen of the maximum thickness for the resolution indicated. In the case of the thickest specimens in the series the image intensity was very low and focussing was difficult.
Some Aspects of the Biological Application of High Voltage Electron Microscopy
Authors: Mayo C. R. , Beeston B. E. P.
Published: June 2020

This paper correlates some of the parameters involved in the high voltage electron microscopy of biological material and includes some preliminary experimental data obtained with the use of the AEI EM7 high voltage microscope.
Experimental Approach to the Structural Water of Fibrin Molecules. —A Test for Electron Microscopic Models
Authors: Köppel G. , Vacca J. G.
Published: June 2020

Clots of bovine fibrinogen and test thrombin (Behringwerke) were standardized with respect to dry weight and dimensions, placed in a modified Millipore Filter System, exposed to a continuous air stream of high humidity and thus subjected to a slow drying process. The clots collapsed in a symmetrical manner, and their heights were reduced from approximately 8 mm at zero hour to 180-230/μm after 5 hours and to 50/μm after 12 hours of drying. The heights of the collapsed clots were measured after dehydration and embedding in Epon 812.

The water content of the clots after various times of drying was determined from the difference of their wet weights and their dry weights which were taken after heat drying at 105°C. If the water content is plotted versus time of drying, a biphasic drying curve results showing the presence of three phases: 1) during the first 3½ hours of the experiment water evaporates at a fast rate, 2) then the curve levels at a water content of approximately 84% water by weight.
Scanning Electron Microscopy of the Red Pulp of the Spleen
Authors: Miyoshi Masayuki
Published: June 2020

In spite of various attempts, conclusive evidence to explain blood passage in the splenic red pulp does not seem to have been presented. Scanning electron microscope (SEM) observations on the rabbit spleen, originally performed by us, revealed that the sinus was lined by a perforated lattice composed of longitudinally extended rod cells and transverse cytoplasmic processes, and that perforations in the lattice were continuous to the spaces among the stellate reticulum cells of the cord. In the present study the observation was extended to the dog and rat spleens, in which the cord is more developed than in the rabbit in order to clarify the possible differences in the fine structure of the sinus wall. An attempt was also made to examine the development and distribution of macrophage in the blood passage of the red pulp.

Spleens were washed and fixed by perfusion with Ringer solution and then with buffered glutaraldehyde. Small tissue cubes were dehydrated with acetone, dried in air and heated with gold. Observations were made by a JEOL SEM Type-3. One air dried tissue cube was cut into small pieces and post fixed with buffered OsO4 for examination under the transmission electron microscope (TEM).
A Unique Cell Contact in the Adrenal Cortex
Authors: Friend Daniel S.
Published: June 2020

A unique periodic structure exists between cortical cells in all zones of the mature rat, guinea pig, and human adrenal gland. This singular zonule is most highly developed between the lateral cell surfaces and between the basilar, perisinusoidal, interdigitating microvilli in the zona fasciculata and occasionally occurs between microvilli of the same cell. In the rat, its fine structure is not appreciably altered by hypophysectomy or adrenocorticotrophic hormone stimulation.

In views which crisply reveal the unit membrane architecture of the smoothly parallel plasma membranes, the 250-350-Å intercellular space is bisected by a series of circles 80-150 Å in diameter varying widely in center-to-center spacing (160-400 Å). This area of contact resembles the zonula continua in its appearance after aldehyde, OsO4, and aldehyde-OsO4-phosphotungstic acid fixation and in its facile digestibility by protease in Epon sections.
Mitochondrial Transformations in the Crayfish Y-Organ During Molt
Authors: Couch Ernest F.
Published: June 2020

Crustacea, like insects, possess ecdysial glands that produce a hormone governing molting and growth. The hormone is a steriod and the same steroid has been found in insects. The steriod has been given several names, among them are crustecdysone and ecdysterone. The ecdysial glands in insects are named prothoracic glands while the homologous structures in crayfish and other Crustacea are called Y-organs. Y-organs do not always contain the same titer of ecdysterone (Passano and Jyssum, 1963), having the greatest amount of the hormone during the period preceding ecdysis. The cyclical activity of the gland is controlled by a neurosecretory hormone, the molt inhibiting hormone (MIH), released by the sinus gland.

Y-organs for this study were obtained from the crayfish, Procambarus simulans. They were fixed with either 3% glutaraldehyde followed by 1% osmium tetroside or simply fixed in buffered 1% osmium. Tissues were embedded in Araldite 502 and prepared for electron miscroscopy. Glands were taken from animals in various periods of the molt cycle.
Cytoplasmic Invaginations in Trophoblasts and Epithelial Cells of Rat
Authors: Baccarini Iracema M.
Published: June 2020

Some morphological nuclear features (invaginations) in normal and abnormal cells have been described in several electron microscopic studies. They have been referred to by others as blebs, loops, pockets, sheets, bodies, nuclear inclusions and cytoplasmic invaginations. Identical appearing structures were found in cells of the uterine cervical epithelium, in trophoblasts of blastocysts and in trophoblasts of rat placenta.

Methods. Uterine cervix (normal rats), rat placenta (9-10 days gestation) and blastocyst were placed in 3% glutarahdehyde for 3 hours. The tissue was washed in phosphate buffer for 24 hours, postfixed in 1%. buffered osmium tetroxide for 1-2 hours and embedded in epon araldite. Sections were double stained with uranyl acetate and lead citrate and viewed in E. M. Siemens 200.

Observations. Nuclear invaginations were found in basal, parabasal and mucous cells of the cervix epithelium, in trophoblasts of blastocyst and in trophoblasts of placenta. An oval, round or elongated invagination contained heterogenously cytoplasm surrounded by a double intact membrane; usually several invaginations were found in the same nucleus.
Ultrastructural Changes Associated with Alcoholic Hyalin in Hepatocytes and Biliary Epithelial Cells
Authors: Minick Odell T. , Yokoo Hidejiro , Batti Fawzia
Published: June 2020

To learn more of the nature and origin of alcoholic hyalin (AH), 15 liver biopsy specimens from patients with alcoholic hepatitis were studied in detail.

AH was found not only in hepatocytes but also in ductular cells (Figs. 1 and 2), although in the latter location only rarely. The bulk of AH consisted of a randomly oriented network of closely packed filaments measuring about 150 Å in width. Bundles of filaments smaller in diameter (40-90 Å) were observed along the periphery of the main mass (Fig. 1), often surrounding it in a rim-like fashion. Fine filaments were also found close to the nucleus in both hepatocytes and biliary epithelial cells, the latter even though characteristic AH was not present (Figs. 3 and 4). Dispersed among the larger filaments were glycogen, RNA particles and profiles of endoplasmic reticulum. Dilated cisternae of endoplasmic reticulum were often conspicuous around the periphery of the AH mass. A limiting membrane was not observed.
High Voltage “Electron Petrography” of Lunar Minerals
Authors: Fisher R. M. , Lally J. S. , Radcliffe S. V. , Heuer A. H. , Christie J. M. , Griggs D. T.
Published: June 2020

Thin sections of selected areas of lunar rocks returned by the Apollo 11 and 12 missions have been studied by high voltage electron petrography (i.e., transmission microscopy). The techniques involved have been described in detail elsewhere.

Three of the principle minerals present in the samples, ilmenite (FeTiO3), plagioclase (CaAl2Si208) and clinopyroxene (Fe,Mg,Ca)SiO3, were examined and compared with terrestrial equivalents.

Dislocations were evident in all three phases in rock 10029. The arrays, in ilmenite and plagioclase (Figure 1) indicate that mild plastic deformation has occurred. Partial recovery is suggested by hexagonal networks in plagioclase and small dislocation loops in ilmenite. In addition, the plagioclase exhibited extensive twinning and fine precipitates were present in both these phases. “Black spot” images characteristic of radiation damage were found in occasional areas of the plagioclase and pyroxene phases.
Effects of Hyperoxia on Lung Utrastructure
Authors: Harrison Gladys
Published: June 2020

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.

Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.
Intensity Profile of Electron Beam
Authors: Ohr S. M. , Noggle T. S.
Published: June 2020

In situ studies of electron displacement damage in graphite are being made in Oak Ridge using a 200 kV Hitachi HU 200-E electron microscope. Examples of the damage structure that develops in the area upon which the illuminating beam is incident are shown in Fig. 1. The spot structures (both black and white) are identified as clusters of interstitial atoms. It is of particular interest in this study to have accurate electron dosimetry in order to relate the damage structures to theoretical models. In this paper we wish to report on the technique and some preliminary results obtained in measuring the intensity profiles of the electron beam.

Measurements of the beam profiles have been made by replacing one of the side windows of the viewing chamber with a 1” brass plate in which is mounted a retractable arm which can insert a Faraday cup into a position on the axis and at a level approximately one-third the distance from the projector lens to the viewing screen. This arrangement allows one to take pictures with the cup in position, and from the shadow it casts determine its effective area in the magnified image of the beam.
Fine Structural Localization of Acyltransferases Involved in Lipid Synthesis in Intestinal Mucosa.
Authors: Barrnett R. J. , Higgins J. A.
Published: June 2020

The main products of intestinal hydrolysis of dietary triglycerides are free fatty acids and monoglycerides. These form micelles from which the lipids are absorbed across the mucosal cell brush border. Biochemical studies have indicated that intestinal mucosal cells possess a triglyceride synthesising system, which uses monoglyceride directly as an acylacceptor as well as the system found in other tissues in which alphaglycerophosphate is the acylacceptor. The former pathway is used preferentially for the resynthesis of triglyceride from absorbed lipid, while the latter is used mainly for phospholipid synthesis. Both lipids are incorporated into chylomicrons. Morphological studies have shown that during fat absorption there is an initial appearance of fat droplets within the cisternae of the smooth endoplasmic reticulum and that these subsequently accumulate in the golgi elements from which they are released at the lateral borders of the cell as chylomicrons.

We have recently developed several methods for the fine structural localization of acyltransferases dependent on the precipitation, in an electron dense form, of CoA released during the transfer of the acyl group to an acceptor, and have now applied these methods to a study of the fine structural localization of the enzymes involved in chylomicron lipid biosynthesis. These methods are based on the reduction of ferricyanide ions by the free SH group of CoA.
The Ultrastructure of Myocardial Cells in Normal and Cardiac Lethal Mutant Mexican Axolotls, (Ambystoma Mexicanum)
Authors: Lemanski Larry F. , Bertke Eldridge M. , Justus J. T.
Published: June 2020

A recessive mutation has been recently described in the Mexican Axolotl, Ambystoma mexicanum; in which the heart forms structurally, but does not contract (Humphrey, 1968. Anat. Rec. 160:475). In this study, the fine structure of myocardial cells from normal (+/+; +/c) and cardiac lethal mutant (c/c) embryos at Harrison's stage 40 was compared. The hearts were fixed in a 0.1 M phosphate buffered formaldehyde-glutaraldehyde-picric acid-styphnic acid mixture and were post fixed in 0.1 M s-collidine buffered 1% osmium tetroxide. A detailed study of heart development in normal and mutant embryos from stages 25-46 will be described elsewhere.
Freeze-Cleave Studies of Lamprey Epidermal Mucous Cells
Authors: Downing Stephen W. , Roth Sanford I.
Published: June 2020

The lamprey epidermis is composed of three cell types, I.e., mucous cells, club cells, and granular cells. By far the most common of the three, the mucous cells are found throughout the epidermis and along the epidermal surface. Like most other vertebrate epidermal cells, the lamprey epidermal mucous cells have numerous membrane specializations, including desmosomes, tight junctions, zonulae occludens. The mucous cells lining the lamprey epidermal surface actively release membrane-bound mucous droplets onto the epidermal surface. Freeze-cleave and freeze-etch techniques have been applied to the lamprey epidermis in order to study the cell membrane structure during release of mucus droplets and maturation of the epidermal mucous cells.
Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum
Authors: Madden P. A. , Anderson W. R.
Published: June 2020

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.
The Fine Structure of the Heart of Owl Monkeys (Aotus Trivirgatus) Infected with Human Malaria (P.Falciparum)
Authors: Merrill Thomas G. , Wellde Bruce T.
Published: June 2020

Recent attempts to elucidate morphological changes associated with clinical, biochemical and immunological findings in human malaria, especially at the ultrastructural level, have met with limited success due in part to the unavailability of fresh human biopsy material. The establishment of P.falciparum in Aotus trivirgatus has made it possible to obtain fresh tissue suitable for pathologic studies at both the light and electron microscopic levels. This experimental host, in some respects, parallels human P.falciparum infections, and experiments utilizing this model would correlate the pathologic features common to the two hosts, further defining the etiology of human P.falciparum infections. Previous clinical and immunologic studies of P.falciparum infected owl monkeys have indicated that the heart is one of the major sites of schizogony of the malaria parasite. The present report describes the ultrastructural changes of the heart associated with P.falciparum infections in the owl monkey.
Fine Structure of Armillaria Mellea Hyphae
Authors: Bal Arya K. , Singh Pritam
Published: June 2020

Armillaria mellea(Vahl ex Fr.) Rummer is an important pathogen, causing “shoe-string”root rot of forest trees; its impact on coniferous plantations in Newfoundland has been realized only recently. Growing interest in the fungus and the disease has led to research on the finer aspects of the pathogen. Attempts to elucidate the ultrastructure of the rhizomorph, have been made recently by Motta and that of the hyphae by Berliner and Duff. The present investigation includes certain aspects of the fine structure of young hyphae, hitherto not dealt with.

The fungus was isolated from mycelial fans present under the bark of infected roots ofPicea glauca(Moench) Voss and maintained on 2% Malt extract agar. Peripheral hyphae from 22 days old culture were scraped off from the surface of the medium and fixed in a mixture of paraformaldehyde-glutaraldehyde in Sorensen's buffer pH 7.2. This was followed by post osmication in 1% 0s04 and subsequent Epon embedding.
Diagnostic Value of Electron Microscopy in Soft Tissue Tumors
Authors: Fine Gerald , R. Morales Azorides
Published: June 2020

For years the separation of carcinoma and sarcoma and the subclassification of sarcomas has been based on the appearance of the tumor cells and their microscopic growth pattern and information derived from certain histochemical and special stains. Although this method of study has produced good agreement among pathologists in the separation of carcinoma from sarcoma, it has given less uniform results in the subclassification of sarcomas. There remain examples of neoplasms of different histogenesis, the classification of which is questionable because of similar cytologic and growth patterns at the light microscopic level; i.e. amelanotic melanoma versus carcinoma and occasionally sarcoma, sarcomas with an epithelial pattern of growth simulating carcinoma, histologically similar mesenchymal tumors of different histogenesis (histiocytoma versus rhabdomyosarcoma, lytic osteogenic sarcoma versus rhabdomyosarcoma), and myxomatous mesenchymal tumors of diverse histogenesis (myxoid rhabdo and liposarcomas, cardiac myxoma, myxoid neurofibroma, etc.)
Preliminary Studies on Heterotopic Calcinosis
Authors: Scott J.R. , Marshall R.B. , Roberts D.K.
Published: June 2020

Interstitial calcinosis and tumoral calcinosis lesions were studied ultrastructurally and with the use of enzyme cytochemistry. Technics for alkaline phosphatase, acid phosphatase, atpase and aryl sulfatase were utilized after removal of calcium salts with EDTA.

Granular elements were seen in both lesions. These granules were seen to lie in cystic spaces of the lesions (Figure 1). Also seen were aggregates of these granules which had apparently calcified (Figure 2). The lesion of tumoral calcinosis had many multinuclear giant cells present peripheral to the cystic spaces with macrophages contributing to the cell population. The lesions all had a pseudocapsule of fibrous connective tissue and “active” connective tissue cells were seen near the cystic space.
Phase Contrast Electron Microscopy and Compensation of Aberrations by Fourier image Processing
Authors: P. Erickson Harold , Klug A.
Published: June 2020

The effects of spherical aberration and defocussing on the electron microscope image are much more simply and directly interpreted in the Fourier transform of the image than in the image itself. In terms of a linear or first order theory of image formation, the two dimensional transform of the image intensity is related to the transform of the projected (two dimensional) mass density of the specimen, by the expression:
Attempts of Resolution of the Subunit Structure of Ferritin and Apoferritin by Electronmicroscopy
Authors: Hawkins H. , Mergner W. J. , Henkens R. , Kinney T. D. , Trump B. F.
Published: June 2020

Ferritin is a high molecular weight protein (462,000), composed of 20 apparently identical subunits which form a hollow shell 120 Å in diameter (Harrison). High resolution electron micrographs reveal a dense core (Fig. 1) containing variable amounts of iron hydroxyphosphate complex surrounded by a shell of protein. The protein becomes visible by the use of negative staining in which it appears as a ring structure, the center being overlaid by the dense core (Fig. 2). X-ray diffraction (Harrison) suggested that the subunits are arranged in the form of a dodecahedron (Fig. 5). During the course of our work it became desirable to visualize directly the fine structure of the ferritin and apoferritin molecules in order to follow structural alterations which might occur in different cell compartments, particularly during the transformation of ferritin to hemosiderin in digestive vacuoles.
Structure and Function of the Superficial Corneal Epithelium
Authors: Kuwabara Toichiro
Published: June 2020

The surface of the cornea is extremely smooth. The glassy surface of the normal cornea appears to be maintained by retention of the tear film over the epithelium. The superficial cells of the corneal epithelium have fine ridges measuring 0. 5 μ high, 0.3 μ wide, and 0. 5-1 μ long. The ridges give a worm-like appearance and are slightly less conspicuous in the central portion. There is a ridge-free zone at the cell boundary (Fig. 1A). These ridges are consistently found in all normal animals. The cytological structure viewed by transmitting electron microscopy appears similar to that of microvilli (Fig. IB).
Deformation Replication
Authors: Temple Black J.
Published: June 2020

Tool materials used in ultramicrotomy are glass, developed by Latta and Hartmann (1) and diamond, introduced by Fernandez-Moran (2). While diamonds produce more good sections per knife edge than glass, they are expensive; require careful mounting and handling; and are time consuming to clean before and after usage, purchase from vendors (3-6 months waiting time), and regrind. Glass offers an easily accessible, inexpensive material ($0.04 per knife) with very high compressive strength (3) that can be employed in microtomy of metals (4) as well as biological materials. When the orthogonal machining process is being studied, glass offers additional advantages. Sections of metal or plastic can be dried down on the rake face, coated with Au-Pd, and examined directly in the SEM with no additional handling (5). Figure 1 shows aluminum chips microtomed with a 75° glass knife at a cutting speed of 1 mm/sec with a depth of cut of 1000 Å lying on the rake face of the knife.
Trophoblast Cell Membrane Interactions at Implantation
Authors: Enders A. C.
Published: June 2020

The alteration in membrane relationships seen at implantation include 1) interaction between cytotrophoblast cells to form syncytial trophoblast and addition to the syncytium by subsequent fusion of cytotrophoblast cells, 2) formation of a wide variety of functional complex relationships by trophoblast with uterine epithelial cells in the process of invasion of the endometrium, and 3) in the case of the rabbit, fusion of some uterine epithelial cells with the trophoblast.

Formation of syncytium is apparently a membrane fusion phenomenon in which rapid confluence of cytoplasm often results in isolation of residual membrane within masses of syncytial trophoblast.
Often the last areas of membrane to disappear are those including a desmosome where the cell membranes are apparently held apart from fusion.
Cylindrical Lens Analysis of Repeating Structures in the Meiotic Synaptonemal Complex
Authors: Roth Thomas F.
Published: June 2020

Between paired chromosomes, there is found a specialized structure called the synaptonemal complex (SC) (Fig. 1). Depending upon the particular stage of synapsis, the SC is seen to consist of dense lateral components (LC) and medial units (MU) which bridge the space between the lateral components. The sub-structure and the finer dimensions of the SC are more difficult to determine in some systems than they are in others. In an attempt to carefully define the dimensions of the SC, to be able to quantify the effects of inhibitors which affect the structure of the SC, a cylindrical lens analysis was used. This method used to reinforce the periodicity found in collagen, relies for its effect on the ability of the lens to image object points as lines. In practice, rotation of the lens relative to the image being analyzed superimposes and thus reinforces those object points arranged in lines in the negative, thereby producing denser more elongate lines.
Aberrations in the Transmission Electron Microscope
Authors: Ploc R.A.
Published: June 2020

Three aberrations contribute to the loss of image resolution in the transmission electron microscope; spherical (SA=Csα3), chromatic (CA=Ccα△VV-1) and diffraction (DA=O.61ƛα-1). For high voltage incident electrons and thin materials most microscopists assume resolution is controlled by spherical and diffraction aberrations. We shall discuss whether equating the SA and DA to derive an optimum aperture size (related to αo) and resolution limit (1) is a valid procedure.

To determine △V for a given material requires the use of either the Bethe or Landau equations. The Landau formula can be used to give the width of the energy spectrum and the Bethe equation, the mean energy loss after the incident electrons pass through the foil. Since the former is the most probable quantity contributing to CA, Figures 1 and 2 are based on the use of the Landau equation. Zirconium of thickness, t, will be considered for the accelerating voltages 105and 106eV.
A 60° Double Tilt Stage for the AEI EM802
Authors: Lucas J. H.
Published: June 2020

In most cases a specimen stage with ±25° tilting facilities is sufficient for contrast analysis of defects in metals and alloys. In order to carry out crystallographic analyses on specimens of cubic symmetry a tilt of about ±45° is necessary. For more general crystallographic analyses on specimens of lower or unknown symmetry, a stage providing angles of tilt of about ±60° is required. There has for some time been a demand for a high angle tilting stage which can be used in a high resolution electron microscope. A 60° double tilting stage to meet the following requirements has been built for the AEI EM802.
Phase Contrast in the Scanning Transmission Electron Microscope
Authors: Thomson M. G. R.
Published: June 2020

It has already been shown 1,2,3 that the phase contrast in both the scanning transmission electron microscope and the conventional electron microscope is given by the same expression provided that the angular correspondences in Fig. 1 are maintained. This provides much useful information to the scanning microscope user as it suggests many phase contrast and interference techniques which may be used. However, the scanning microscope is a more flexible instrument, particularly with regard to the choice of the aperture angle βo and the use of a spectrometer between object and detector. In order to observe these phase effects it is necessary for the illuminating scanning spot to possess transverse coherence. This implies both that the chromatic aberration and the paraxial image of the electron source be small compared with the diffraction aberration.
Resolution of a Transmitted Electron Image Formed by A Scanning Electron Microscope
Authors: Takashima S. , Hashimoto H. , Kimoto S.
Published: June 2020

The resolution of a conventional transmission electron microscope (TEM) deteriorates as the specimen thickness increases, because chromatic aberration of the objective lens is caused by the energy loss of electrons). In the case of a scanning electron microscope (SEM), chromatic aberration does not exist as the restrictive factor for the resolution of the transmitted electron image, for the SEM has no imageforming lens. It is not sure, however, that the equal resolution to the probe diameter can be obtained in the case of a thick specimen. To study the relation between the specimen thickness and the resolution of the trans-mitted electron image obtained by the SEM, the following experiment was carried out.
Three Dimensional Replication of Fatigue Cracks by Vacuum Infiltration for Study of Crack Tip Morphology by Scanning Electron Microscopy
Authors: Shaw G. G.
Published: June 2020

I. Introduction: Fatigue investigators have been looking at crack tips by examining the surface and by sectioning the crack. Much useful information has been obtained by these methods, but a look at the complete crack in three dimensions with the tip intact yields much new information. This is especially true when one is able to examine the crack tip in full tension or compression or stages in between, by using the following techniques.

II. Vacuum Infiltration in Situ: The crack is generated on a fatigue machine using a sheet sample with a notched central hole. If one desires to replicate in full tension, the machine is stopped in tension and the apparatus shown in Figure 1 is clamped to the sides of the sample.
Electron Microscopy of A U-Nb-Zr Alloy
Authors: Nolan T. A. , Allard L. F. , Johnson D. H.
Published: June 2020

The γ phase of the U/7.5 wt % Nb/2.5 wt % Zr alloy is a BCC structure of average atoms which exists at 800°C. The ordered γs phase forms upon quenching; it is thought the ordering is due to a shift of the body centered atoms in correlated <100> directions (Fig. 1a). The γs phase is described as being BCC with an antiphase structure of domains 50 to 100 A in diameter produced by a variation in the correlation shift direction from region to region.
Substructure of Cu and Cu Al Alloys Following Explosive Shock Deformation at One Megabar Pressure
Authors: Hooker S. V. , Foltz J. V. , Grace F. I.
Published: June 2020

In the past decade electron microscopy has proven a most valuable tool for studies of microstructural changes in materials due to planar wave shock loading. Although the nature of the defect structures as a function of solute content has been investigated rather thoroughly for many alloys for pressures up to 500 kbar, and a few studies for specific metals have been reported for pressures in the megabar range, to date no systematic study has been carried out for alloys of a particular family shock loaded to a pressure of one megabar. In this paper we examine the shock deformation behavior of Cu, Cu95 Al5, and Cu89 Al11 solid solutions for a pressure of one megabar. For producing a planar wave loading situation the explosive assembly of McQueen and Marsh was duplicated.1 Annealed specimens were placed in foil form in a sandwich arrangement and simultaneously shock loaded. A water tank was used for recovery purposes.
Comparison of Recovery and Recrystallization in Stainless Steel Following Plane-Wave Shock Loading and Explosive Forming
Authors: Korbonski J. A. , Murr L. E.
Published: June 2020

Comparison of recovery rates in materials deformed by a unidimensional and two dimensional strains at strain rates in excess of 104 sec.−1 was performed on AISI 304 Stainless Steel. A number of unidirectionally strained foil samples were deformed by shock waves at graduated pressure levels as described by Murr and Grace. The two dimensionally strained foil samples were obtained from radially expanded cylinders by a constant shock pressure pulse and graduated strain as described by Foitz, et al.
Creep Induced Twinning in A Γ'-Precipitation Hardened Nickel-Base Alloy
Authors: Kear B. H. , Oblak J. M. , Leverant G. R.
Published: June 2020

High temperature nickel-base alloys are strengthened by a high volume fraction, coherent precipitate of γ’ [Ni3 (Al,Ti)], with Ll2 structure. The mechanical properties of these alloys are dependent upon the interaction of dislocations with the ordered γ’ precipitate. A detailed diffraction contrast analysis has been made of dislocation/ γ’ particle interactions occurring during 1400oF creep of the nickel-base alloy Mar-M200.

In the early stages of creep, two types of γ’ particle shearing mechanisms have been observed, Fig. 1. The interpretation of these micrographs is illustrated in Fig. 2.