bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arrangement of microtubules and microfilaments during oriented secondary wall formation
Authors: Seagull R. W. 
Published: June 2020

Introduction. Microtubules have long been hypothesized to function as track-like elements, directing cellular components (Hepler & Palevitz 1974). In higher plants, cortical microtubules (cmt) have been hypothesized to function in this manner in the orientation of secondary wall microfibrils (MF) (reviewed by Heath, 1974). Involvement in such a process requires that the cmt be close to the structures being moved, be parallel to the direction of orientation and be of sufficient length to function as guide elements. In radish root hairs, sub-pl cmt occur along the length of the hair, paralleling the secondary wall MF. Root hair elongation occurs via tip growth, which results in simultaneous deposition of primary, randomly arranged MF (first 25 μm of root hair) and secondary, oriented MF (distances greater than 25 μm, Fig. 1).Results. Longitudinal serial sections show that cmt start and terminate randomly throughout the length of the hair, but are absent in the tip region (0-3 μm from tip). Microtubules are rarely found more than 500 nm from the pl. Bridges between cmts and the pl are evident, Fig. 4. In the region between 20 and 60 μm from the tip, 50% of the cmt are less than 1 μm long.
Crystalline structure in the milk fat globule membrane (MFGM)
Authors: Wooding F.B.P. 
Published: June 2020

The MFGM has been suggested (Patton and Keenan 1975) to be a very convenient and readily available source of plasma membrane from an active secretory cell. It can easily be isolated in pure form by churning or freeze thawing washed cream. However, there is also evidence (Wooding 1977) that the MFGM is not only a simple unit membrane structure such as is found for other isolated plasmalemmas. Characteristically, it has a coat of material 10-20 nm thick on one side which is derived from the cytoplasm of the mammary alveolar secretory cell.The milk fat globule secreted from the mammary alveolar cell has a continuous unit membrane boundary with a thin but uniform zone of cytoplasmic material between this membrane and the fat droplet core (Fig 1, inset). Immediately after the release of the milk fat globule from the secretory cell this “initial” MFGM undergoes rapid changes which produce a stable inhomogeneous “secondary” milk fat globule boundary characteristic of the fat globules in the milk of any species.
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).
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.
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.
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.
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
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

IntroductionThe 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 MethodsIn 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 DiscussionThe 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.