bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural study of the early development of the gregarine parasite grebneckiella nixellae misra
Authors: Dass C. M. S. , Singotam L. 
Published: June 2020

Eugregarines, amongst all the sporozoans are unique in that the trophozoite shows the differentiation of the body into three distinct zones a. epimerite, b. protomerite and c. deutomerite. G. pixellae. which is a parasite in the midgut of the common centipede Scolopendra marsitans. is a typical example of eugregarines and was used in this study to trace the ultrastructural features of the various zones of the trophozoite as well as the development of these structures during the early (intra-cellular) part of the life cycle.Sporozoite which is released from the spore in the midgut of the host, has an ellipsoid shape and a very simple organization. The body, enveloped by a typical plasma membrane, contains a centrally placed nucleus, a few mitochondria and a large number of electron dense granules. The sporozoites make their way into the epithelial cells lining the midgut and start intracellular development. The sporozoite become oval and increase in size.
An ultrastructural study of the pathogenesis of the arteriosclerotic lesions in the spontaneous hypertensive (SHR) rat strain
Authors: Yajima G. , Kurihara S. , Ida M. , Aihara K. , Asano G. , Sohn T. J. , Kwon H. Y. 
Published: June 2020

The spontaneous hypertensive rats are the strain which was isolated by Okamoto et al and is known to cause high frequency of spontaneous hypertension in later stage of life. Some of them are also recongnized to have high frequency of the cerebro-vascular accident and is also designated as apoplexy prone strain. The genetic and etiological factors of this spontaneous hypertension are the matters of the extensive survey of the investigators, however, the morphological aspects of this specific strain of causing the hypertension still await further confirmation in future. In this viewpoint, the authors have undertaken the electron microscopic and cytochemical electron microscopic studies of the various arteries in a rather extensive manner.The spontaneous hypertensive rats were supplied from the animal room of the University of Kyoto by courtesy of Drs. Okamoto and Yamori. The rats were kept on the commericially available solid diet and sytolic blood pressure was measured and scored daily.
Electronmicroscopic and biochemical studies on surfactant of fetal newborn and adult rat lungs
Authors: Yasuda Hiromoto , Toida Suzuko , Kosakai Mamoru , Ueda Nobuo , Takahashi Ichiro 
Published: June 2020

Materials and methods:Pulmonary surfactant from lung homogenates of fetal, newborn and adult S. D. strain rats, prepared using differential and discontinuous density gradient of Nacl solution(Katyal, et. al., 1977), were fixed with 2. 5% glutal aldehyde with 2% tannic acid (Kalina, M., et. al. 1977), for 2 hours and post-fixed with 1% OsO4 solution for 2 hours.The other part of surfactant of same materials fixed with 2. 5% glutal aldehyde, added with 30% glyserol for prevention of ice crystal formation, were chilled by liquid nitrogen and placed in the HUS-5GB with block type freeze-fracture apparatus.Thin film of carbon replicae were made with shadowed by Pt. and Pd., mounted on copper grids. Lung tissues prepared for usual electron microscope studies were in one part, embedded in Epon 812, and, the others, also made thin film of carbon replica for freeze-fracture study. Surfactant from lung homogenates, and lung tissues prepared for usual electronmicroscopic studies were dehydrated by gradual alcohol series, embedded in Epon 812, sectioned by MT-2(Porter type), or Reichert type ultramicrotomes, mounted on copper grids, and stained with uranyl acetate and lead citrate.
Phagocytosis of particles by alveolar macrophages
Authors: Chao J. , Tausch J. , Biggar W. D. , Sturgess J. M. 
Published: June 2020

The alveolar macrophage plays a key role in pulmonary defense. It functions in the clearance of particles from the peripheral lung, although the cellular mechanisms and factors which influence its function are poorly understood. In the lung, macrophages vary in size and distribution in peripheral airways and in the alveoli where they are closely associated with the alveolar wall.The mechanism of phagocytosis has been investigated with rat alveolar macrophages in vitro, comparing two different particle types: a large particle (zymosan) and a smaller, bacterial particle (Staphylococcus aureus). Alveolar macrophages were isolated from rat lung by bronchial lavage and incubated in vitro in two culture systems: one with cells in suspension and one with cells adherent to a glass substrate. The cells were then challenged with non-opsonised or opsonised particles for various time intervals. The interaction of particles with the cell surface, their ingestion and, for bacterial particles, killing was examined, correlated and quantitated by scanning and transmission electron microscopy and by bacteriological assays.
Fine structure of human sperm entry into zona-free hamster oocyte
Authors: Barros C. , González J. , Herrera E. , Bustos-Obregón E. 
Published: June 2020

Zona-free mammalian oocytes have been observed to fuse, under in vitro conditions, With non-homologous spermatozoa. Taking advantage of this heterologous gamete fusion, we designed a bioassay to test -by means of zona-free hamster oocytes- the fertile ability of human spermatozoa, from semen samples of patients attending an Infertility Clinic. To further validate our bioassay, which Was reported elsewhere, we studied the behavior of gamete membranes during fusion at the ultrastructural level.Zona-free hamster oocytes were mixed in vitro with human spermatozoa. At different times after the start of incubation, oocytes were fixed in 1% glutaraldehyde in 0. 25M cacodylate buffer pH 7. A and post-fixed in 196 osmium tetroxide. After dehydration in acetone, they were embedded in a low viscosity epoxy resin. Ultrathin sections were stained with uranyl acetate and lead citrate and examined with a Phillips 300 electron microscope.
Characterization of mammary cells from the lactating rat by electron microscopy
Authors: Sadhukhan P. , Chakraborty J. , Soloff M. S. , Wieder M. H. , Senitzer D. 
Published: June 2020

The means to identify cells isolated from the mammary gland of the lactating rat as a prerequisite for cell purification have been developed.The cells were isolated from mammary tissue with 0. 1% collagenase, and they were visualized by scanning and transmission electron microscopy and by alkaline phosphatase cytochemistry.The milk-secreting cells have surface microvilli, whereas the surface of the myoepithelial cells is smooth (Fig. 1). The two isolated epithelial cell types are readily distinguishable by transmission electron microscopy (Fig. 2). The secretory cells contain vacuoles and a relatively extensive rough endoplasmic reticulum, whereas the myoepithelial cells contain a more osmiophilic cytoplasm, contractile filaments (Fig. 3) and elongate processes. These features are consistent with the appearance of the two cell types in situ.Incubation of isolated cells with oxytocin prior to glutaraldehyde fixation resulted in the contraction of the myoepithelial cell processes (Figs. 4 & 5). This physiological response to oxytocin shows that the isolated myoepithelial cells were intact. The appearance of isolated secretory cells was unchanged by the presence of oxytocin.
Fine structure of the spermatozoon of Proteocephalus longicollis (Cestoda proteocephalidea)
Authors: Swiderski Z. , Eklu-Natey R. D. 
Published: June 2020

The spermatozoon of the proteocephalid cestode Proteocephalus longicollis (Zeder, 1800) is a very elongate, thread-shaped cell, about 300 μ m long and 0, 1 - 0, 9 pm in diameter, with no differentiation into head, midpiece and tail.The spermatozoon body (Figs. A-K) consists of: (a) two axonemes of the unique “9+1“ pattern, (b) an elongate nucleus, (c) numerous electron-dense, glycogen-like granules of different sizes and shapes and (d) cortical, cytoplasmic microtubules associated with the limiting plasma membrane. The total lack of acrosome and mitochondria is a remarkable and unusual finding which seems to be characteristic for all cestode spermatozoa examined so far.The nucleus of the spermatozoon, narrow and rod-shaped in its anterior part, becomes progressively enlarged and flattened toward the posterior end. The nuclear envelope is relatively thick and composed of two wavy membranes (Figs. G and H). The nucleoplasm is very loose and consists of fine filaments and granules of chromatin.
Some aspects of the fine structure of goldfish optic tectum
Authors: Roots Betty I. 
Published: June 2020

In teleosts the optic tectum is the major integrative centre in the brain. The cyto- and fibre architecture of the optic tectum have been studied extensively and a well-defined laminar pattern has been described. Here some aspects of the fine structure of the optic tectum of the goldfish, Carassius auratus, will be described and discussed. Goldfish which had been kept at a temperature of 15°C were fixed by perfusion with 2. 5% glutaraldehyde in a phosphate buffer. After fixation pieces of the optic tectum from both dorsal and ventral regions, cut so that their original orientation in the tectum could be determined by their shape, were removed. They were post-fixed in 1% osmium tetroxide in the same buffer for 1 1/2 h, dehydrated, stained in 2% uranyl acetate and embedded in epon. Sections were stained with lead citrate.Lining the ventrical is the ependyma consisting of epithelial-like cells which are 5. 4 μm in diameter, are ciliated, and joined by both desmosomes and tight junctions between their somata.
Effects of temperature on coated vesicle formation within pre-synaptic terminals in cat sympathetic ganglia stimulated in vitro
Authors: Kadota Tomoko , Kadota Ken 
Published: June 2020

Many workers have shown the depletion of synaptic vesicles following nerve stimulation but there is a discrepancy among data regarding the appearance of coated vesicles attendant on the decrease in the number of synaptic vesicles (Heuser and Reese, 1973; Ceccarelli et al., 1973; Pysh and Wiley, 1974). The present experiment was an attempt to investigate the effect of temperature on stimulation dependent coated vesicle formation.Dissected cat superior cervical ganglia were incubated in Krebs solution at 10°C and 37°C respectively. Preganglionic nerves were stimulated with the electrical parameters consisting of 1 msec square pulses of 20 V at 10 Hz for 30 min. After stimulation the ganglia were fixed with 2 % 0s04 (lh). To examine the participation of the coated endocytosis on recovery processes some ganglia were stimulated at 37°C for 30 min and then rested either at 37°C or 10°C for 5 and 15 min before fixation. The fixed material were then processed for electron microscopy with conventional method consisting of uranyl acetate block stain (30 min), dehydration with ethanol series, and embedding in Epon 812.
Ultrastructural localization of neuropeptides in the rat brain
Authors: Van Leeuwen F.W. 
Published: June 2020

In order to obtain specific and optimal ultrastructural localization of vasopressin and oxytocin in the hypothalamo-neurohypophyseal system of the rat, 2 staining procedures and several tissue treatments were evaluated using neurohypophyseal tissue. It appeared from these studies that post-embedding staining with the unlabeled antibody enzyme method developed by Sternberger allows greater dilution of the first antibody (anti-vasopressin, 1:4800) than the indirect procedure (1:320) using a peroxidase conjugate as second antibody. Immersion fixation with 4% formalin during 24 hours gave better results (general ultrastructure, immunoreactivity) than those obtained by perfusion fixation with 2.5% glutaraldehyde-1% paraformaldehyde or freeze substitution.Since no reliable specificity tests were performed at the electron microscopical level, tests were developed for antibodies against both vasopressin and oxytocin. For anti-vasopressin plasma neural lobes of homozygous Brattleboro rats, that are lacking vasopressin by a genet- ical defect, were used. For antibodies against both hormones serial sections were used that were alternately incubated with the antibodies.
Electron microscopic studies of the brain edema after local brain injury in animals with changed immunological reactivity
Authors: Gannushkina I. V. , Sukhorukova L. I. 
Published: June 2020

It is well established at present that the course of pathological processes in local brain trauma depends on immunological reactivity of the organism and to a great extent on its sensitization to brain antigens.This study was undertaken to clarify the early ultrastructural changes of the nervous tissue in perifocal area of local brain wound in normal rabbits, those sensitized to brain antigens or desensitized by brain antigens after preliminary sensitization. In addition, the influence of sensitization and desensitization per se on brain tissue ultrastructure was studied. The animals were sensitized and desensitized with intravenous and intraperitoneal 20% water-salt extract of homologous brain tissue. The immunological state of the animals was checked by using the complement fixation test. The fixation of antibrain antibodies in perifocal area of the wound was studied by the direct Coons immunofluorescence method.
Low sulphur content in atrophied human skeletal muscle: an electron probe X-ray microanalytical study
Authors: Wróblewski R. , Gremski W. , Roomans G. M. , Nordemar R. , Edström L. 
Published: June 2020

Many diseases of the human skeletal muscle involve an atrophy of the muscle fibres. In some cases mainly one of the fibre types is affected. The fibre typing system used in this study is that of Padykula and Herman, 1955 and distinguishes between type I fibres which presumably correspond to the slow-twitch fibres and type II fibres which are the fast-twitch fibres. The type II fibres can be divided into type II A, II B and II C fibres. Recent advances in instrumentation and tissue preparation have permitted an investigation of the elemental composition of individual muscle fibres of known fibre type with the aim of comparing healthy and atrophied muscle fibres.In this study we have examined ten patients suffering from rheumatoid arthritis, two patients suffering from Parkinson's disease and two patients with upper motor lesions. As a control group we have examined muscles from eight healthy controls of the same age.
Electron microscope tracing of acid mucopolysaccharides after administration of dihydrotachysterol
Authors: Regal Dan-Sook 
Published: June 2020

Nonspecific calcinosis engendered by dihydrotachysterol ( DHT ) is associated with massive extraosseous calcium deposits, in connection with which acid mucopolysaccharides ( AM ) can be observed. Cardiac muscle and the vascular system are particularly affected. The acri-flavine-phosphotungsten acid ( PTA ) contrast-method of tracing AM is based on the affinity of acriflavine for basophile material in the tissue. An electron dense contrast is achieved by means of the complex of acriflavine, which is selectively bound in the tissue, and PTA.Six month old albino rats were sacrificed 1, 2, 3, 5, 8, 10, 13, 17 and 20 days after per os-administration of 3. 0 mg DHT. Tissue samples from cardiac muscle and aorta were first fixed in 2 % glutaraldehyde phosphate-buffer, pH 7. 0 for two hours and then pre-incubated in darkness with 2. 0 x 10-2 M acriflavine in 50 % ethanol phosphate-buffer overnight.
The diagnosis of metabolic storage disease in skin biopsies (a light-, electronmicroscopic, and analytical study)
Authors: Jurecka W. , Gebhart W. , Lassmann H. 
Published: June 2020

Diagnosis of metabolic storage disease can be established by the determination of enzymes or storage material in blood, urine, or several tissues or by clinical parameters. Identification of the accumulated storage products is possible by biochemical analysis of isolated material, by histochemical demonstration in sections, or by ultrastructural demonstration of typical inclusion bodies. In order to determine the significance of such inclusions in human skin biopsies several types of metabolic storage disease were investigated. The following results were obtained.In MPS type I (Pfaundler-Hurler-Syndrome), type II (Hunter-Syndrome), and type V (Ullrich-Scheie-Syndrome) mainly “empty” vacuoles were found in skin fibroblasts, in Schwann cells, keratinocytes and macrophages (Dorfmann and Matalon 1972). In addition, prominent vacuolisation was found in eccrine sweat glands. The storage material could be preserved in part by fixation with cetylpyridiniumchloride and was also present within fibroblasts grown in tissue culture.
Freeze-etch studies of epiphyseal growth plate cartilage reveal matrix vesicles associated with calcification
Authors: Cecil Russell N. A. , Clarke Anderson H. 
Published: June 2020

Unfixed proximal tibial epiphyseal growth plates were studied by freeze-etch to confirm the presence of extracellular calcifying matrix vesicles and to determine the substructure of matrix vesicle membranes as compared to plasma and other membranes of intact chondrocytes. Growth plates from 6-10 week old Sprague-Dawley rats were cut into 1x3 mm blocks whose long dimension was oriented either perpendicular or parallel to the long axis of the tibia. Some blocks were fixed at pH 7. 0 in 0. 2M cacodylate - buffered 2. 5% glutaraldehyde for 1 hour at 4ÅC. The blocks were immersed in 30% glycerol solution at 4ÅC for 1 hour, frozen in liquid nitrogen, and then fractured, etched for 2 minutes, and coated with platinum, carbon and 0. 2% Formvar solution. The replicas were cleaned with chromic acid, floated onto Formvar coated grids, and examined with a Phillips EM 300 electron microscope.Fixed and unfixed specimens appeared similar in ultrastructure. Chondrocytes, matrix, and matrix vesicles were identified. In specimens fractured parallel to the long axis of the tibia, the reserve, proliferative, hypertrophic, and calcifying zones could be discerned as described by light and electron microscopy.
HVEM studies of the calcified bone interface with endosteal dental implants
Authors: Steflik D. E. , Song M. J. , Sjsk A. L. , Parr G. R. , Hanes P. J. , McKinney R. V. , Singh B. B. , Brewer P. 
Published: June 2020

Previous studies have suggested the prerequisite of bone interfacing successful endosteal dental implants. This is the concept of osseointegration of dental implants within the jaw. However, the ultrastructure of the actual bone interface is largely unknown. This current study is planned to elucidate with correlative high-voltage electron microscopy (HVEM) and conventional electron microscopy (TEM), the morphology of the interface of the support tissues to endosteal dental implants. All ultrastructural protocols involve undecalcified tissue sectioning.After 2 months healing following extraction of all premolars, 120 root form and blade-type endosteal dental implants were placed into the mandibles of 30 adult mongrel dogs. This report will be restricted to 12 implants retrieved from animals euthanized after 5 months of unloaded healing. Following perfusion with buffered 3% glutaraldehyde the implants were block resected with their encasement of mandibular tissues, fixed by immersion for 24 hr in glutaraldehyde and postfixed with 1% OsO4 for 2 hr.
Quantitative mapping of skeletal muscle fibers by x-ray microanalysis: Effect of long-time storage of freeze-dried cryosections
Authors: T. High , R. Nassar , I. Taylor , B. Scherer , P. Ingram , J.R. Sommer 
Published: June 2020

Electron probe X-ray microanalysis (EPXMA) is uniquely capable of performing quantitative topochemical analyses with high spatial resolution of elemental concentrations in cryosections from quickfrozen biological material. EPXMA requires very expensive instrumentation and maintenance, and data acquisition is very time consuming. For economic reasons, it is most desirable that any EPXMA facility serve several users who, while waiting for their turn, may need to store cryosections for a time. Storage of cryosections is associated with loss of structure and, under certain circumstances, also with changes in elemental distribution after short periods of time. We have re-examined several cryosections by EPXMA mapping that had been stored under vacuum for very long periods of time.Materials and Methods:Single, intact semitendinosus muscle fibers from R. temporaria were quick-frozen as previously described. The cryosections were freeze-dried in a Balzers FDU 101 and carbon-coated before external transfer to plastic desiccators in which they were stored under vacuum. Quantitative EPXMA maps were obtained as previously described (Figs.1A-F).Results and Conclusions:In the maps [Ca] was very high in the JSRs and, occasionally, (Fig. 1D) seen in hot spots that may correspond to spotty accumulations of negatively charged electron-dense material often seen in the free SR away from JSR. Overall, only small variations in elemental distribution or concentration were observed after storage for over one year; the significance of these variations (especially with such elements as Na) is difficult to assess because of the small number (4) of muscle fibers examined. The lighter region in the center of Fig. 1B is a result of slight etching due to extended static probes that were taken from this area in addition to mapping. JSR [Ca] remained remarkably constant after one year of storage. Freeze-dried cryosections revealed some smearing of structural detail, ranging from minimal to moderate, especially in the myofibrillar compartment (cf. Figs 1A,B). Our findings show that, when handled properly, carbon-coated cryosections can be stored over extended periods of time with minimal loss of structure or changes in elemental distribution. Thus, quantitative EPXMA image maps after long storage present a rather accurate representation of the original. Proper storage of freeze-dried cryosections is a viable procedure for the effective participation of independent research groups in multiple-user EPXMA facilities, access to which may occasionally require prolonged storage periods.
Detection of human cytomegalovirus infection in paraffin sections by modified Steiner silver stain for LM and TEM
Authors: Chien K. , Kim Y.K. , Shintaku I.P. , Van de Velde R.L. , Heusser R.C. , Geller S.A. 
Published: June 2020

Human cytomegalovirus (HCMV) infection is encountered more frequently in surgical specimens due to the increased number of immunosuppressed patients (organ transplants or HIV positive). Previous studies showed that HCMV infected cells in paraffin sections can be precisely labelled by in situ hybridization or by Grocott's methenamine silver stain for LM and subsequently confirmed by TEM. However, further studies indicate HCMV infection can also be identified by modified Steiner silver stain3 but in a different manner.Modified Steiner silver stained paraffin sections can be processed for TEM as follows: Coverslips are removed by immersion in xylene. A few drops of 1% OsO4, freshly dissolved in xylene, is then pipetted onto each slide for 5 minutes. Aqueous OsO4 can not be used as it will destain the sections instantly. Slides are rinsed in xylene, xylene/acetone and then 100% acetone. The sections are infiltrated with epoxy resin/acetone, embedded in epoxy resin, polymerized and subsequently separated from slides by heat as previously described.