bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Three Common Fixatives on Bacteria
Authors: Hanson J.M. , Pfister R.M. , Smucker R.A. 
Published: June 2020

The ultrastructure of the cytoplasmic membranes, cell walls, and mesosomes of Escherichia coli and Bacillus megaterium were found to be significantly affected by different fixation procedures.Logarithmic cells were divided into equal portions and different fixation procedures employed. A 6% glutaraldehyde solution followed by 1% 0s04 fixa-tion (1). The Ryter-Kellenberger (R-K) fixation (2) and Luft's ruthenium red (R-R) (3). The glutaraldehyde-OsO4 and R-K were post fixed with 2% and 0.5% uranyl acetate respectively. Thin sections were post stained with uranylacetate and lead citrate. One sub-portion of Bacillus megaterium was criti-cally-point dried. Glutaraldehyde-OsO4 critically-point dried whole mounts (Fig. 1) showed little background material and smooth walls. The R-K cells (Fig. 2) had irregular outer walls. The R-R cells (Fig. 3) were irregular and revealed external polysaccharide. There is a distinct difference in the internal morphology of the wall layers using the E. coli (Figs. 4,5,6). A heavier staining of the CM was observed in B. megaterium (Fig. 7).
Ultrastructural Characteristics of an Organism Intimately Associated with Necrotic Bone in Gangrenous Stomatitis (Noma)
Authors: Merrell B.R. , Joseph S.W. 
Published: June 2020

Gangrenous stomatitis (noma) is a severe disfiguring, gangrenous condition involving the cervicofacial region of young children in the underdeveloped areas of the world. It begins as an indurated papule in the premolar or molar area of the mouth. Progression is rapid and insidious, eventually leading to extensive destruction of the facial structures, including the soft tissue, bone, and teeth. Rapid onset of secondary infection has made effective bacteriological studies difficult and confusing (1). Several types of bacteria, chiefly anaerobic, have been implicated as primary pathogens. The present paper describes an ultrastructural study of necrotic bone from paraffin embedded material collected in Indonesia from advanced cases of noma, showing a close association between a microorganism and the necrotic bone.Figure 1 shows that the colonization of the bone by the organism presents as a brush border-like layer, consisting of long filamentous, rod-shaped organisms overlaying an irregular surface of bone.
Scanning Electron Microscopy of African Swine Fever Virus in Tissue Culture
Authors: Breese S. S. , Pan I. C. 
Published: June 2020

Previous studies of African swine fever virus (ASFV) development and its hemadsorption property by transmission electron microscopy showed virus emergence from the cells (1) and the attachment of infected cells to red cells (2). The scanning electron microscope has been used in the present study to examine the surfaces of infected leucocytes and Vero cells. Leucocytes prepared from swine blood were grown in buffer in Leighton tubes containing glass microscope cover slips and infected with ASFV Lisbon '60 strain prepared from tissue culture. After 1 hr. incubation at 37°C, the inoculum fluid was removed and replaced with F15 balanced salt solution maintenance fluid and 10% foetal bovine serum. The Vero cell cultures were grown and infected in a similar manner. Observations were made starting 18 hrs. after infection.The cover slips were washed gently with Sorenson's buffer pH 7.3, fixed in 2% Glutaraldehyde in Sorenson's buffer and post-fixed in 2% osmic acid in Sorenson's buffer. Dehydration with graded alcohols was followed by immersion in amyl acetate.
Immuno-Electron Microscopic Study on the Pulmonary Metastases of Chang' s Hepatoma Cells
Authors: Chew E. C. , Sun C. N. , White H. J. 
Published: June 2020

The study of tumor metastasis has long been a subject of interest in cancer research because it is one of the principal problems in malignancy that prevents successful local treatment. The purpose of this communication is to report the sequence of metastasis of Chang's hepatoma cells studied by immuno-EM techniques.The use of peroxidase-labelled antifibrin antibody to demonstrate fibrin in early stages of metastases has been described earlier (1). Rats were killed at different time intervals, ranging from 5 minutes to 1 month after tumor cell innoculation. Small pieces of lung tissue were fixed in 4% phosphate buffered glutaraldehyde and post-fixed in 1% oxmium tetroxide. Routine procedures were followed for dehydration and embedding in Epon 812. Sections were stained with uranyl acetate and lead citrate.The fine structure of Chang's hepatoma cells has been reported elsewhere (2,3). At 5 minutes after IV injection, tumor cells were found in the pulmonary vessels.
Differential Lability of Spindle Microtubules in Crane-Fly Spermatocytes
Authors: Janicke Marie A. , LaFountain James R. 
Published: June 2020

A well-established property of cytoplasmic microtubules is that they rapidly depolymerize in vivo and in vitro when the temperature of the medium is dropped to 0-4°C. In the case of the mitotic spindle, which contains hundreds of microtubules, it has been shown that microtubules attached to the kinetochores of chromosomes appear to be more stable to cold shock than are the more numerous non-kinetochore microtubules, which are not attached to chromosomes (1). These results led us to inquire into the possible universality of differential lability of spindle microtubules as well as to speculate on possible factors that could give rise to this phenomenon.Our approach was to incubate spermatocytes of crane flies (Nephrotoma suturalis) in cold Ringer's solution, fix them in cold, buffered glutaralde- hyde at intervals of 7, 15, 30 and 60 minutes after the start of cold shock, post-fix in osmium tetroxide and then process them for embedding in epoxy resin.
Morphological Changes in the Rat Granulosa Cell Surface During Differentiation Induced by Estradiol and Gonadotropins
Authors: Bagavandoss P. , Richards JoAnne S. , Midgley A. Rees 
Published: June 2020

During follicular development in the mammalian ovary, several functional changes occur in the granulosa cells in response to steroid hormones and gonadotropins (1,2). In particular, marked changes in the content of membrane-associated receptors for the gonadotropins have been observed (1).We report here scanning electron microscope observations of morphological changes that occur on the granulosa cell surface in response to the administration of estradiol, human follicle stimulating hormone (hFSH), and human chorionic gonadotropin (hCG).Immature female rats that were hypophysectcmized on day 24 of age were treated in the following manner. Group 1: control groups were injected once a day with 0.1 ml phosphate buffered saline (PBS) for 3 days; group 2: estradiol (1.5 mg/0.2 ml propylene glycol) once a day for 3 days; group 3: estradiol for 3 days followed by 2 days of hFSH (1 μg/0.1 ml) twice daily, group 4: same as in group 3; group 5: same as in group 3 with a final injection of hCG (5 IU/0.1 ml) on the fifth day.
A Scanning Electron Microscopic Study of the Inner Surface Appearance of the Alveolar Capillary
Authors: Wang N.S. , Wei F. , Charbonneau M. 
Published: June 2020

Capillary networks interwave with elastic fibers (1) in alveoli and are focally sleeved by myofibroblasts (2) or held apart by pillar or "posts" (3). All these structures are implicated in the regulation of the capillary flow by light and transmission electron microscopic studies. The endothelium of the alveolar capillary is also known to be active metabolical- ly. The present paper presents some morphological evidences of these implicated functions on the inner surface of the alveolar capillary.The pulmonary artery of rabbit lungs was cannulated and perfused successively with heparinized normal saline, veronal acetate buffered 3% glutaral- dehyde solution, buffer solution without fixative, followed by saturated uranium acetate water solution at 30 cm H2O pressure while the lung was positively inflated with room air at either 5 or 15 cm H2O pressure. The hardened lungs were then sliced and dehydrated with graded acetone, cryo- fracture in liquid nitrogen, critical point processed, and examined with a scanning electron microscope.
Fine Structural Alterations in Thyroid Follicular Cells (FC) and Changes in Serum Thyroxine Produced by Feeding Polychlorinated Biphenyl (PCB) to Rats
Authors: Collins W.T. , Capen Charles C. , Kasza Louis 
Published: June 2020

The widespread contamination of the environment with PCB, a compound used extensively by industry in hydraulic and heat transfer fluids as well as plasticizers and solvents in adhesives and sealants, has resulted in detectable tissue levels in a large portion of the human population, domestic animals, and wildlife. Intoxication with PCB produces severe hepatic necrosis, degeneration of lymphoid tissues and kidney, skin lesions, decreased reproductive performance, reduced feed efficiency, and decreased weight gain. PCB also has been reported to reduce the binding of thyroid hormone to serum proteins and enhance the peripheral metabolism of thyroxine with increased excretion of thyroxine-glucuronide in the bile (Bastomsky, Endocrinology 95: 1150-1155, 1974).The objectives of this investigation were (1) to investigate the histopathologic, histochemical, and ultrastructural changes in thyroid FC produced by the acute (4 week) and chronic (12 week) administration of low (50 ppm) and high (500 ppm) doses of PCB to rats, (2) to correlate these alterations to changes in serum immunoreactive thyroxine concentration, and (3) to investigate the persistence of the effects of PCB on the thyroid gland.
Changes in Hepatocytes During Extracorporeal Perfusion of Canine and Porcine Livers
Authors: Menz L.J. , Ruwart M.J. , Kaminski D.L. 
Published: June 2020

In a study designed to evaluate the performance of isolated perfused liver, a structural-functional correlation was made which included physiological, biochemical, and ultrastructural analysis. The livers from adult dogs and young pigs were prepared for cannulation of the artery, the veins, and the bile duct while observing a minimum ischemic time of a few minutes. The perfusate consisted of heparinized, oxygenated whole blood maintained normothermic as it entered the liver via the portal vein and hepatic artery for periods ranging from 2 to 5 hours.Throughout the perfusion, portal venous pressure was monitored, bile production was determined every 10 minutes and pyruvate output was obtained from continuous autoanalysis of perfusate before entry and after leaving the organ. Samples for electron microscopy were taken before cannulation, immediately after transfer to the perfusion apparatus (15 minutes post-cannulation), and every hour thereafter.
Quantitative Reduction of Desmosomes in Malignant Meningiomas
Authors: Liszczak T. , Kleinman G. , Richardson E.P. , Kornblith P. 
Published: June 2020

Among the ultrastructural features that characterize human meningiomas are interdigitating cell processes connected by desmosomes which are surface specializations for intercellular relationships. These desmosomes are fairly constant in meningiomas of different histological subtypes and lend themselves to quantitative study. Occasionally invasive malignant meningiomas occur. These malignant meningiomas have surface properties different from the non-invasive tumors. In examining tissue sections from invasive and non-invasive tumors we found a reduction in the desmosome number in the malignant tumors.Portions of tumors were placed into 2.57, glutaraldehyde in the operating room, postfixed in Dalton's chrome osmium, stained en bloc with uranyl acetate and embedded in Epon 812. Sections were lead citrate stained. For quantitation, random 200 mesh grid squares were photographed at low magnification, 3000x. The same squares were examined at 20,000x and desmosomes were counted (Dn). Since multinucleation is uncommon in meningiomas, the low magnification photographs could be examined and the number of nuclei and presumably total cell number recorded (Cn).
Extraocular Muscle Pathology in Aperts Syndrome
Authors: Pachter Bruce R. , Margolis Shelia , Davidowitz Jacob , Breinin Goodwin M. 
Published: June 2020

Aperts disease or Acrocephalosyndactyly described by Apert1 consists of oxycephaly (tower skull), exophthalmos, strabismus, antimongloid fissures, syndactyly (fusion of fingers, 2-4). This syndrome frequently involves ocular motility disturbances.: the latter have been suggested to result from mechanical limitations of the globe which are secondary to the bony malformation of the orbit2. Up until this time the question of a structural abnormality existing in the extraocular muscles themselves has not been investigated. The present light and electron microscopic study examined a segment of the inferior oblique muscle taken from a patient with Aperts syndrome.The right inferior oblique muscle from a patient with Aperts syndrome was completely disinserted and an 8mm segment was taken from its belly portion. The specimen was fixed initially in 1% paraformaldehyde-1% glutaraldehyde in phosphate buffer for 4 hrs, then transferred to 4% glutaraldehyde overnight. The muscle segment was postfixed in 1% osmium tetroxide, dehydrated in graded alcohols, embedded whole in Epon 812, and serially sectioned at 15 microns.
Histogenesis of Human Extraocular Muscles and Its Innervation
Authors: Martinez A. Julio , Barmada M. 
Published: June 2020

Embryonic myogenesis and neurogenesis of human extraocular muscles (EOM) were studied by light and electron microscopy in a group of embryos and fetal specimens (6 to 24 weeks gestational age) (20 to 200 mm CR length).The earliest trace of EOM in humans have been reported at 7 mm (4 weeks) as a single undifferentiated mass of condensed paraxial mesoderm surrounding the optic vesicle. There is no separation between individual muscles. The distinction occurs before the 20 mm stage (6-7 weeks) when the 4 recti and the 2 obliques can be recognized(1). The oculomotor nerve can be identified as an elongation of the midbrain at 12.2 mm (5th week). The trochlear nerve appears between the 6th and 7th weeks and the abducens nerve is recognizable first at 31.3 mm (8th week). By the end of the 8th week, all the nerves had reached their respective muscles.
Effect of Tocopherol Pretreatment on the Incidence of Adriamycin-Induced Murine Cardiomyopathy
Authors: Liss R.H. , Ifrim I. , Myers C.E. 
Published: June 2020

Adriamycin, an important new anticancer drug, has exhibited significant chemotherapeutic activity against a wide spectrum of human neoplasms. However, this anthracycline induces an irreversible, delayed cardiac toxicity in both man and in laboratory animals. The cardiotoxicity is believed to follow peroxidation of cardiac lipid by adriamycin (1). Recently, it has been reported that both the lipid peroxidation and cardiac toxicity that follow administration of adriamycin are reduced by pretreatment with the free radical scavenger, tocopherol (2). The present study was undertaken to compare the incidence of adriamycin-induced cardiomyopathy in rodents treated with (a), the compound alone and (b), adriamycin and tocopherol.One group of CDFp male mice received alpha-tocopherol (85 units, I.P.) 24 hours prior to the administration of adriamycin (15 mg/kg, I.P.). A second group was dosed identically with adriamycin, without tocopherol pretreatment. Both groups of mice were sacrificed 5 days following drug administration and myocardium from left ventricles was excised, fixed in glutaralde- hyde and prepared for electron microscopy.
Extended Perfusion for Long-Term Preservation of Whole Hearts
Authors: Philpott D. E. , Moretti R. L. , Harrison G. , Klein G. , Abraham S. , Kato K. 
Published: June 2020

One of the problems associated with heart transplants is the maintenance of the donor heart while the recipient is being prepared. The present method, which entails keeping the body of the donor alive as a sort of incubation chamber, is expensive and difficult. Maintenance of the heart in vitro would not only cut costs, but also allow greater flexibility in recipient selection, location and timing of the operation.To determine the effects of preparing hearts for perfusion maintenance, rat hearts were excised and prepared for retrograde perfusion via the aorta. Once excised, the hearts were cooled in iced Tyrode's solution saturated with 95% O2 and 5% CO2 during the preparation for perfusion. Warm Tyrode's (37°) containing 2% plasma was then flushed through the heart at 100mm Hg pressure for 3 min., 15 min., 30 min. and 1 hour.
Fine Structure of Some Plethodontid (Caudata: Plethodontidae) Spermatozoan Cytoplasmic Droplets
Authors: Wortham J. W. E. , Vernick S. H. , Morrison J. E. , Patek D. R. , Thompson S. M. 
Published: June 2020

Spermatozoan cytoplasmic droplets have been noted in a variety of animal species. Although their function and chemical nature is as yet undetermined, Noble and Weber (1) suggested that droplets in plethodontid salamanders are useless vestiges retained on the mature spermatozoa, while Murphy et al. (2) have suggested that the cytoplasmic droplets may play some role in sperm maturation. The object of the present study is to determine the morphology and chemical nature of these droplets at the light and electron microscopy level.In our studies of spermatozoan cytoplasmic droplets, we used the sperm from Plethodon jordani and Desmognathus ochrophaeus (Caudata, Plethodontidae). The droplets were observed in testicular material of both species and from spermatozoa taken from the vas deferens of Desmognathus ochrophaeus, and were most often found associated with the middle piece of the spermatozoa. The droplets were limited by a single membrane and located on the side of the axial rod opposite the undulating membrane and flagellum (Fig. 1 and 2).
Ultrastructural Response of Rat Adenohypophysis to Phenothiazines
Authors: Sarphie T.C. 
Published: June 2020

Phenothiazine derivatives are known to have direct actions upon the hypothalamus which influences the secretory activities of the adenohypophysis. Previous studies indicate that such derivatives as chlorpromazine, perphenazine and trifluoperazine inhibit the release of FSH and LH while facilitating the release of prolactin all of which blocks ovulation, suppresses estrous cycles, causes infertility and pseudopregnancy and induces lactation (1,2). To morphologically correlate these endocrine responses with phenothiazine treatment, this paper surveys the ultrastructural features of the gonadotrophic secretory cell types in the adenohypophyses of rats treated with the aforementioned, commercially available compounds.Changes in the ultrastructure of the gonadotroph-secreting cells became evident after only 3 days of drug treatment with obvious increases in numbers and sizes of secretory granules accompanied by pronounced dilatation of the endoplasmic reticulum. The presence of these larger granules represents a fundamental cellular mechanism in the adenohypophysis for handling excessive hormone produced during the suppression of secretion (3).
Transmission Electron Microscopy Studies of Pore Cells in Limax Maximus
Authors: Beltz B. S. 
Published: June 2020

The cells which are described in this study surround the salivary nerve of the terrestrial mollusc, Limax maximus. The salivary system of Limax consists of bilateral glands, ducts, and nerves. The salivary nerves originate at the buccal ganglia, which are situated on the posterior face of the buccal mass, and run along the salivary duct to the gland. The salivary nerve branches several times near the gland, and eventually sends processes into the gland.The pore cells begin to appear at the first large branch point of the salivary nerve, near the gland (Figure 1). They follow the nerve distally and eventually accompany the nerve branches into the gland tissue. The cells are 20-50 microns in diameter and contain very small nuclei (1-5 microns) (Figure 2).The cytoplasm of the pore cells is segregated into a storage area of glycogen and an organelle region located in a band around the cell periphery (Figure 3).
Effect of Contraceptive Steroids on the Endometrium of Guinea Pig: SEM study
Authors: Said Mai M. , Nayak Ramesh K. , McCoy Randall E. 
Published: June 2020

Burgos and Wislocki described changes in the mucosa of the guinea pig uterus, cervix and vagina during the estrous cycle investigated by transmission electron microscopy. More recently, Moghissi and Reame reported the effects of progestational agents on the human female reproductive tract. They found drooping and shortening of cilia in norgestrel and norethindrone- treated endometria. To the best of our knowledge, no studies concerning the effects of mestranol and norethindrone given concurrently on the three-dimensional surface features on the uterine mucosa of the guinea pig have been reported. The purpose of this study was to determine the effect of mestranol and norethindrone on surface ultrastructure of guinea pig uterus by SEM.Seventy eight animals were used in this study. They were allocated into two groups. Group 1 (20 animals) was injected intramuscularly 0.1 ml vegetable oil and served as controls.
Image reconstruction of low and high dose micrographs of negatively stained glutamine synthetase
Authors: Frank J. , Goldfarb W. , Kessel M. 
Published: June 2020

Recent studies of biological specimens with long range crystalline order have demonstrated a significant improvement in resolution when the radiation level is of the order of 0.5e/Å2 and care is taken to sustain the specimen in an inert medium such as glucose rather than negative stain. A large class of biological molecules exists, however, which do not form crystalline arrays and where the population exhibits a random distribution of projected views.In a preliminary communication we have demonstrated the possibility of applying a computer averaging procedure to such negatively stained individual molecules which produces the equivalent result to that of averaging over a number of unit cells in a crystal lattice. The present study extends these methods to assess the effect of electron dosage on negatively stained protein molecules by a comparison of averages of high and low dose micrographs of the same particles.The protein chosen for study is the enzyme glutamine synthetase isolated from E. coli and purified according to Valentine.
Ultrastructural localization of soluble and insoluble 3H-methyl prednisolone as revealed by electron microscopic dry-mounting radioautography
Authors: Nagata T. , Yoshida K. , Ohno S. , Murata F. 
Published: June 2020

IntroductionSince the recent improvements in both techniques and development in equipments at our laboratory or others, the dry-mounting procedures for radioautography facilitated the wide application of them for the study of soluble compounds such as nucleic acid precursors, amino acids, carbohydrates, lipids and steroids at both the light and electron microscopic levels. The purpose of this paper is to demonstrate ultrastructural localization of both soluble and insoluble 3H-labeled methyl prednisolone, a synthetic corticosteroid, by means of dry-mounting procedure at the electron microscopic level.Materials and MethodsMouse liver slices obtained from a male mouse and cultured HeLa cells were pulse- labeled in vitro in Eagle's MEM containing 6α-methyl prednisolone-1,2-T sodium succinate (100μCi/ml) for 1 hour.Some specimens were quickly frozen in isopentane cooled to -160°C with liquid nitrogen and freeze-dried,fixed in osmium vapour, embedded in Epon, dry-sectioned and dry-mounted according to the procedure described previously, by means of wire loops using Sakura NR-H2 emulsion containing dioctyl sodium sulfosuc- cinate in order to prevent the emulsion films from bursting while they are air dried.