An analytical electron microscope study of the kinetics

The detection and quantification of the segregation of Bi to grain boundaries in Cu using Analytical Electron Microscopy is demonstrated and the effects of time and temperature are observed. The experimental data are compared with the theoretical prediction of McLean’s segregation isotherm. Special grain boundaries are also considered. The analysis shows that the detection of the variation of segregation with time and temperature as well as grain boundary characteristics is possible using analytical electron microscopy and that the quantification techniques used here agree well with theoretical calculations of the segregant levels.     

Endoscopic study of the small intestine with push enteroscopy. A prospective study

OBJECTIVE: To evaluate whether push enteroscopy of the small bowel (PES), undertaken after extensive previous investigations in suspected intestinal bleeding from an uncertain site, chronic diarrhoea or lymphoma of the small intestine, contributes to the diagnosis, and to ascertain the results of PES and its clinical significance. PATIENTS AND METHODS: 56 consecutive patients (29 men, 27 women; mean age 63 years) were investigated prospectively. The main indications for PES were the search for the source of intestinal bleeding in 79% of patients (group A), chronic diarrhoea or tropical sprue in 16% (group B) and search for tumour of lymphoma in 5% (group C). PES was always performed in fasting patients under sedation/analgesia using a video PES, which contrary to catheter enteroscopy provides a channel for intervention. RESULTS: In group A 27% of patients were found to have lesions, in particular angiodysplasias, or (in once case) leiomyoma. Half of these patients were successfully treated endoscopically without later surgical intervention being required (mean follow-up of six months). In the other half operation became necessary, either because the disease itself indicated it or the bleeding persisted, the source being in the more distant small intestine and thus not accessible to endoscopic intervention: only 50% of the length of the small intestine proved to be within reach of the instrument. No abnormalities were discovered in patients of groups B and C. CONCLUSION: In cases of gastrointestinal bleeding from an uncertain source PES should be performed first, because in many cases it may obviate surgical intervention. But PES seems to contribute little of diagnostic value in other indications.     

Granulocytic-macrophagic and macrophagic colony stimulating factors elicit colonies of mast cells in mouse bone marrow agar culture. An electron microscope study

The aim of this paper is to describe a new methodology for the separation of human high-density lipoproteins (HDL) into apolipoprotein (apo) E-poor and apo E-rich subfractions by fast protein liquid chromatography (FPLC) using a heparin affinity column. Recoveries for apolipoproteins AI, AII, CI, CII, CIII, and E were 68.9, 74.7, 71.9, 73.5, 40.0, and 55.8%, respectively. We provide suggestive evidence that apo E-rich HDL is produced from apo E-poor HDL by the displacement of apo AI by apo E. Apo E-poor HDL was the predominant fraction. The molar ratio of apo E to apo AI in apo E-poor HDL was 0.02 and 0.01 for the subjects studied while in apo E-rich HDL it was 1.86 and 1.25. The molar ratios of the C apolipoproteins to apo AI are markedly different between the subfractions.     

Subchronic toxicity of pentachlorobiphenyl congeners n. 126 or 118 in the rat liver. An electron microscope study

3,3',4,4',5-Pentachlorobiphenyl (PCB) or congener n. 126 and 2,3',4,4',5-pentachlorobiphenyl or congener n. 118 were given independently to male and female Sprague-Dawley weanling rats. Experimental diets were prepared by dissolving the congeners in 4% corn oil. The congeners were administered as follows: congener n. 126--groups of three animals, either male or female, in each group were placed on the respective diets containing 0.1, 1.0, 10.0 ppb congener, 5.0 micrograms/kg bw loading dose + 10.0, or 100 ppb; congener n. 118--the females were dosed with 2, 20, 200, and 2,000 ppb congener, and the males received 10, 100, 1,000, 10,000 ppb. Thirteen weeks after the start of dosing with the two congeners, liver samples were obtained from all the animals and prepared for electron microscopy. In the congener n. 126-exposed animals, the alterations noted in a dose-related fashion consisted of a marked increase in the profiles of smooth endoplasmic reticulum (SER), and in the heightened number of lipid droplets in many parenchymal cells. Mitochondria showed abnormalities such as dumb-bell shapes, and the cristae parallel to the long axis of the organelle. Lipofuscin granules were numerous in the liver of animals that received 100 ppb of the congener; notably the females of the treatment group expressed this trait more abundantly than the males of the group. We conclude that the compound is mildly toxic. In the animals administered congener n. 118, the alterations were revealed in the liver of both male and female animals in a dose-related manner, also the most evident hepatocyte architectural modifications included an augmentation of SER profiles, mitochondrial aberrations, and an elevated number of lysosomal elements and lipid droplets. Abnormal shapes, and cristae in atypical orientation comprised mitochondrial aberrations. Alterations in the liver morphology of the females were qualitatively similar to those in the males; however, the dose levels used in the latter were five-folds of that which were given to the females. We conclude that the females are more sensitive than the males of the species to congener n. 118. We further conclude that congener n. 118 is less toxic than n. 126 since the lesions were induced by several-folds high dose levels used for the former.     

Acetylcholinesterase distribution in chick spinal cord cultures. A light and electron microscope study

In vitro studies and animal experiments were started for the purpose of following the migration of chloramphenicol marked with 14C from polymerised polymethylmetacrylate cylinders. Test-cylinders were submerged in a physiological saline solution and the 14C concentration followed over a period of 34 days. Two series were started with the cylinders being submerged at intervals of 5 and 40 min after the start of polymerisation. These in vitro studies showed that initially the migration of active substances marked with 14C from the plastic cylinders was extremely high but remained then constant over the whole test period. Over a period of at least 20 days a higher 14C migration was evident in those cylinders submerged in the elution 5 min after the start of polymerisation. In our in vivo studies we implanted test-cylinders into the femur of rabbits. The migration of active substances marked with 14C resulted in 14C-concentrations being present in the surrounding tissues. During the phase of exudation, depending on the operative process, the concentration increased and reached values that remained constant during the phase of recanalisation of the surrounding tissues over a period of up to 6 weeks. Thereafter the concentration of active substances fell. The max. concentration rates of active substances within the boundary layer were between 15 and 20 mug/g humidity weight. After 8 weeks we found concentration rates of approx. 1 mug/g humidity weight. On examining the 14C distribution within the implanted plastic cylinders we observed that in the course of time the boundary layer increased in thickness and a concentration gradient towards the centre had developed. The spread of diffusion gradually seized the deeper layers so that a long-lasting presence of active substances may be expected.     

A scanning electron microscope study of the interstitial tissue of the canine testis

Scanning electron microscopy (SEM) is a potent tool that is especially valuable in interpreting the three-dimensional relationships of cells within tissues. This type of information is obtainable from thin sections in transmission electron microscopy (TEM) only by reconstructions of serial sections. The arrangement of the interstitial cells of the testis in relation to the capillaries and lymphatic channels, in particular, is easier to visualize in SEM than in TEM. Cytoplasmic constituents, as well as cell surface modifications, are demonstrable by this technique. The presence of droplets, presumably lipid droplets, both within and on the Leydig cells and the lymphatic endothelial cells, is quite evident. Other cytoplasmic structures are also apparent. For example, the possible functional significance of "openings" that are seen by SEM on the septa that surround lipid droplets is discussed relative to the appearance of the same area as seen in thin sections or in freeze-fracture replicas. SEM should become a very useful method for studying cytological and morphological alterations that occur in testicular tissue that is subjected to physical or chemical manipulation.     

Development of the thyroid gland in the rat fetus in vivo. An ultrastructural and radioautographic study

A study of the differentiation of the thyroid follicles was carried out in rat fetuses between day 14 of pregnancy, when cellular polarization begins and day 18, when completely formed follicular lumina are differentiated. After day 18, only the shape and the size of the lumina undergo modifications. The mechanism of folliculogenesis involves the participation of several structures. At 14 days of pregnancy, adherens type contact zones with membrane densification appear between the cells. These junctional zones spread out and form infoldings which deeply penetrate the cytoplasm. Golgi vesicles migrate to these zones and they fuse among themselves and with the contact membranes : follicular cavities result which can be recognized as soon as day 16 of pregnancy. A radioautographic study showed the beginning of iodide organification at 17 days 11 hours of pregnancy. From this time onward silver grains were seen over the follicular cavity, even it is still incompletely formed.     

An electron microscope study of the axonemal ultrastructure in human spermatozoa from male smokers and nonsmokers

OBJECTIVE: To investigate possible abnormalities or deterioration of the sperm axonemal ultrastructure in men who have smoked a large quantity of cigarettes (> 20 per day) for a prolonged period. DESIGN: Semen specimens were collected by patients via masturbation; qualitative characteristics of the sperm were assessed and ultrastructural analysis of the sperm axoneme was performed using standard operating procedures for electron transmission microscopy. SETTING: The Andrology Institute of Lexington, Lexington, Kentucky, and the Department of Histology and Embryology, University of Salonika, Greece (collaborative effort). PATIENT(S): Twenty-nine men (mean age +/- SD, 30.7 +/- 2.1 years) who smoked a mean (+/- SD) of 30.7 +/- 2.1 cigarettes per day for 10.7 +/- 0.7 years and 15 men who never smoked (mean age +/- SD, 30.4 +/- 2.2 years) participated in this study. MAIN OUTCOME MEASURE(S): Ultrastructural organization of the sperm axoneme in male smokers and nonsmokers. RESULT(S): Changes in the number and the arrangement of axonemal microtubules were noted in the smoker group when compared to the nonsmoker group. The incidence of axonemal abnormalities was higher in spermatozoa from smokers compared with that in spermatozoa from nonsmokers. CONCLUSION(S): Smoking a large quantity of cigarettes per day, under the conditions of the current study, severely affected the ultrastructure of the flagellum and, more specifically, it affected the axoneme of the human spermatozoon.     

Photochemically induced focal cochlear lesions in the guinea pig: II. A transmission electron microscope study

We report the characterization of a de novo unbalanced chromosome rearrangement by comparative genomic hybridization (CGH) in a 15-day-old child with hypotonia and dysmorphia. We describe the combined use of CGH and fluorescence in situ hybridization (FISH) to identify the origin of the additional chromosomal material on the short arm of chromosome 6. Investigation with FISH revealed that the excess material was not derived from chromosome 6. Identification of unknown unbalanced aberrations that could not be identified by traditional cytogenetics procedures is possible by CGH analysis. Visual analysis of digital images from CGH-metaphase spreads revealed a predominantly green signal on the telomeric region of chromosome 10p. After quantitative digital ratio imaging of 10 CGH-metaphase spreads, a region of gain was found in the chromosome band 10p14-pter. The CGH finding was confirmed by FISH analysis, using a whole chromosome 10 paint probe. These results show the usefulness of CGH for a rapid characterization of de novo unbalanced translocation, unidentifiable by karyotype alone.     

Anti-inflammatory and antisecretory potential of histidine in Salmonella-challenged mouse small intestine

Challenge of mouse small intestinal loops with Salmonella typhimurium invoked the accumulation of luminal fluid, acute inflammation, and extensive structural damage to the small intestinal mucosa, as determined by histology and electron microscopy. Intraperitoneal and intestinal luminal injection of L-histidine, a known antioxidant, reduced the amount of fluid accumulating in the intestinal lumen and protected the intestinal tissue from S. typhimurium-induced damage. The reduction in S. typhimurium-induced fluid accumulation by L-histidine was specific for the L-enantiomer because D-histidine had no significant protective effect. Efficacy of L-histidine in protecting the infected intestinal tissue was attributed to the capacity of the imidazole ring to scavenge reactive oxygen species (ROS) generated by cells in the intestine during the acute inflammatory response. Glutathione levels were markedly reduced in S. typhimurium-challenged, inflamed intestinal tissues as a result of ROS generation. Importantly, after dosing the S. typhimurium-challenged mice with L-histidine, the glutathione content of the small intestinal tissue was not significantly different from mock-challenged controls. Further evidence favoring this mechanism included the capacity of L-histidine to scavenge ROS produced as a result of lipopolysaccharide (LPS) exposure of mononuclear cells (U937), as demonstrated with a redox-sensitive fluorescent dye (2'7'-dichlorodihydrofluorescein [DCF]). Addition of L-histidine, and to a lesser extent D-histidine, to the culture media of U937 cells before LPS exposure, resulted in a significant dose-dependent reduction in LPS-induced intracellular DCF fluorescence, as measured quantitatively by flow cytometry. The potential therapeutic value of anti-inflammatory drugs containing an L-histidine-like structure could protect infected mucosal tissues irrespective of microbial etiology.     

Effects of an ionophore, X-537A, on mouse CNS cultures: a light and electron microscope study

The effects of the ionophore X-537A on organotypic CNS tissue culture were investigated with bright field and electron microscopy. In addition to condensation of mitochondria this agent was found to induce a relatively selective vacuolation of the Golgi apparatus of neurons and glial cells. At the dosages used (50 mug/ml for 2-3 hours and 100 mug/ml for 1 hour) these changes were irreversible. Additional experiments suggested that the cellular effects of X-537A were primarily due to its ability to translocate Na+ across cellular membranes.     

A light and electron microscope study on oogenesis in the freshwater pulmonate snail Biomphalaria glabrata

In the freshwater snail Biomphalaria glabrata the formation and composition of yolk granules and the role of the follicle cells were studied by histochemical and electron microscopical techniques. The rough endoplasmic reticulum and the Golgi apparatus appeared to be involved in yolk formation, which is a continuous process throughout oogenesis. From the very beginning of yolk formation two main types of yolk granules were distinguished morphologically. However, with histochemical and enzyme cytochemical methods no differences were observed between these types. The granules acquire lysosomal enzymes after oviposition, indicating that their main function is probably digestion of perivitelline fluid, which contains nutrients for the developing embryo. Yolk formation and the activity of the follicle cells were studied in successive stages of oogenesis by quantitative electron microscopy. The data strongly suggest that the follicle cells are involved in the formation of the follicular cavity and hence in the ovulation process.     

Leiomyosarcoma of the small intestine and the colorectum. A case contribution

Smooth muscle tumors of the alimentary tract are uncommon. A retrospective study was made of 7 patients treated for leiomyosarcoma of the small and large bowel to identify prognostic factors that influence results. The symptoms associated with these tumors varied according to the anatomic sites of the lesions and the position of the growth in relation to the intestinal lumen but the most common presenting clinical signs are bleeding or obstruction. The differential diagnosis between benign and malignant smooth muscle tumors is sometimes quite difficult. Clinical behavior of the myosarcomas of the gastrointestinal tract can be predicted to a large extent by the site of the tumor, the presence or absence of invasion of adjacent vital organs, and the histopathologic grade of malignancy. Although the mitotic activity of a gastrointestinal stromal tumor remains the most critical prognostic factor, tumors have been seen to recur locally and to metastasize even with rare or absent mitotic figures. Further studies are needed to pinpoint the factors that may be correlated to the prognosis.     

Critical study of electric activity of the small intestine in the dog

Thanks to a cross-circulation, the authors caused to survive in the abdomen of a sacrificed dog, the whole of the small intestine, the motor activity of which was analysed by electro-enterography. This experimental preparation thus eliminates polygraphic recordings of all potential variations outside the small intestine, e.g. stomach, colon, diaphragm, muscle, myocardium. One thus obtains very pure tracings of the variations of potential originating in the small intestine, recorded from bipolar serous intestinal electrodes, they show the activity of the small intestine, consisting of a permanent basal electric rhythm on which are grafted spikes contemporary of motor phenomena. In the abdominal skin there were recorded only a cutaneous slow wave which was contemporary with the deep motor phenomena.     

The mutagenicity of benzo[a]pyrene in mouse small intestine

OBJECTIVE: To determine the effects of controlled ovarian hyperstimulation (COH) on endometrial maturation. DESIGN: Prospective, before and after evaluation of midluteal endometrial biopsies in oocyte donor's spontaneous and subsequent COH cycles. SETTING: Tertiary academic medical center assisted reproductive technologies clinic. PATIENT(S): Nineteen oocyte donors. INTERVENTION(S): Exogenous gonadotropins, endometrial biopsies. MAIN OUTCOME MEASURE(S): Endometrial histology and an immunohistochemical marker of uterine receptivity, the alphavbeta3 vitronectin. RESULT(S): Glandular and stromal dyssynchrony was more common after COH in 16 (80%) of 20 cycles than 6 (30%) of 20 spontaneous cycles (P <.05). Glandular lag was more frequent in COH cycles and unaffected by progesterone administration. The beta3 subunit of the alphavbeta3 vitronectin receptor was present in 9 (45%) of 20 spontaneous and 2 (10%) of 20 COH cycles (P <.05). CONCLUSION(S): Exogenous gonadotropin use in healthy reproductive age women did not result in endometrial evidence of a luteal phase defect. A greater incidence of glandular-stromal dyssynchrony resulted from the use of exogenous gonadotropins. The presence of alphavbeta3 was noted in most endometrial specimens demonstrating in phase glandular maturation. We conclude that endometrial dyssynchrony that results from delayed glandular development most likely represents a normal histologic variant.     

Acceleration of small intestine contrast study by ceruletide

The effect of ceruletide on the small bowel transit time of barium sulfate suspension was studied in 165 patients. The control group consisted of 115 cases. An intramuscular injection of 500--750 ng/kg body weight ceruletide was given in 106 cases (group A), 20 ng/kg ceruletide was intravenously injected in 35 patients (group B), and 40 ng/kg was intravenously injected in 24 cases (group C). The mean transit time in group A was 62 +/- 41 min (mean +/- SD), and 126 +/- 62 min in the corresponding control group of 83 cases. (P less than 0.001). The mean transit time in group B was 65 +/- 50 min, and 69 +/- 56 min in group C, whereas in the corresponding control group of 32 cases the mean transit time was 137 +/- 79 min (P less than 0.01). A normal radiographic pattern was found in 75%, and slightly increased segmental contractions in 21%. Overtonicity and pronounced segmental contractions were seen in 4%. The recommended standardized small bowel study using ceruletide reduces the examination time by roughly one-half and produces simultaneous and uniform opacification of the jejunum and ileum.