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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this paper a technique is described, using Araldite CY 223 and hardener HY 2967 as injection material, for preparing corrosion casts or histological sections. The plastic has a viscosity (at 39-40 degrees C) similar to that of blood, a gelling time of approximately 17 min (at 40 degrees C), and an exothermic transition energy of delta H = 80.28 +/- 3.20 cal/gm. The influence of the plastic on the tissue is discussed. The histological sectioning of fixed tissue containing Araldite-filled blood vessels after embedding in 2-hydroxyethyl-methacrylate (GMA) is described. When using GMA in a modification of the mixtures of Ruddell (1967) and Sims (1974), methylbenzoate is recommended as an intermedium in order to obtain a more uniform infiltration and reproducible section thickness. At the same time methylbenzoate is recommended as a storing fluid. Sections of 2-3 micrometers afford satisfying morphologic and morphometric results. This method allows various arterial wall dimensions to be measured easily, and provides a suitable means to compare histometric values with SEM data derived from corrosion casts.
Anat Rec 1982 Jun
PMID:A new plastic for morphometric investigation of blood vessels, especially in large organs such as the human liver. 711 2

The present study details a new method for the exposure and viewing of individual microvessels located within the small intestine of rats. This procedure will selectively and consistently remove the outer muscle layers and underlying submucosa of the intestinal wall and thereby expose a variety of arterioles in their normal location within the tissue, with their normal relationship to each other undisturbed. The small intestine of the rat was initially fixed by vascular perfusion with 2.5% glutaraldehyde in 0.1 M cacodylate/HCL buffer, reinfused with heparinized whole blood, removed from the animal, and secured to a dissecting petri dish for further fixation. Subsequently, the external muscularis was dissected from the sample which exposed the submucosa. In order to remove the connective tissue elements from this layer and uncover the submucosal vasculature, the samples were first transferred to a solution of 30% potassium hydroxide for 2-5 minutes and then to a final digesting solution containing collagenase. Thereafter, the samples were routinely processed for light microscopy and for scanning (SEM) or transmission (TEM) electron microscopy. Examination of the samples revealed excellent preservation of the three-dimensional organization of the arteriolar wall with minimal membrane damage. This new technique now makes it possible to visualize the shape and position of individual smooth muscle cells along arterioles of differing size and branching order.
Anat Rec 1982 Aug
PMID:A new morphological procedure for viewing microvessels: a scanning electron microscopic study of the vasculature of small intestine. 713 4

An investigation into fibre composition and glycogen depletion pattern within the middle gluteal of 16 horses participating in an 80 km endurance ride was carried out. Although the proportion of slow twitch high oxidative (ST) fibres in the horses varied between 7 and 38 per cent, it was found that the horses with the highest proportion of these fibres usually had the best performance records. The cross-sectional area of the fast twitch low oxidative (FT) fibres was greatest, with the ST and fast twitch high oxidative (FTH) being similar in size. Most marked histological evidence of glycogen depletion after the ride was in the ST fibres, which were apparently totally depleted. A variable degree of depletion was found in both the FTH and FT fibres. Biochemical measurement of muscle glycogen showed a 56 +/- 7.2 per cent (mean +/- SEM) decrease in content.
Vet Rec 1981 Apr 25
PMID:Muscle fibre composition and glycogen depletion in horses competing in an endurance ride. 729 3

The perinotochordal sheath (PNS) is a "tube" of extracellular matrix (ECM) that surrounds the avian notochord beginning in the second day of development. Somites, like the notochord, derive from chordamesoblast but are encased by a less substantial perisomitic matrix (PSM). Initially both tissue types exhibit epithelioid characteristics. Somitic cells subsequently disperse, however, while notochordal histoarchitecture is maintained until much later. To test the possible shape-preserving role of the PNS, otochords were isolated from chick embryos by homogenization (which retains the sheath) or by trypsinization (which removes the sheath). Somites were similarly isolated. Tissues were cultured 12-72 hours and studied by LM, SEM and TEM. Mechanically isolated notochords are initially rigid with smooth surfaces. During the culture period a few cells grow outward from cut ends of the notochord, but its overall rod shape and intact PNS are maintained. In contrast, uncultured trypsinized notochords are flaccid, denuded cylinders with numerous cytoplasmic blebs. They adhere to the substratum within 12 hours of culture when a few cells break away from the central tissue rod, migrate laterally, and appear mesenchymal. This cellular dispersion is directional (perpendicular to the long notochordal axis) and continuous (up to 72 hours). At this time a flattened ovoid growth area is formed. Cultured somites form flat circular growth areas within 12 hours of culture irrespective of the isolation method. These data suggest that the maintenance of an epithelial configuration by notochords in vivo may be due in part to physical restraints of the PNS. It seems possible that notochordal secretions (manifested by the formation of a PNS) could result in its compartmentation and axial confinement while its unrestrained somitic relatives are free to disperse.
Anat Rec 1980 Jun
PMID:Surface ultrastructure of the isolated avian notochord in vitro: the effect of the perinotochordal sheath. 741 18

The time to resumption of ovarian cycles was determined in 27 post partum beef suckler cows by twice weekly milk progesterone analysis and was 24.5 +/ 1.6 (SEM) days. Treatment of 87 cows with a double injection of 500 micrograms cloprostenol at an interval of 11 days resulted in 55 cows (63.2 per cent) responding by a fall in progesterone levels and ovulation. Thirty-eight of these cows (43.7 per cent of total) subsequently conceived to a timed double insemination. Eight (9.2 per cent) had high progesterone levels at the second injection had failed to respond; three (3.4 per cent) had a prolonged period of low progesterone levels after the first injection which were still low when the second was given. A further 21 cows (24.1 per cent) had low progesterone levels at the time of the second injection but could not be categorised further with certainty because of lack of previous samples. These cows were treated at a significantly earlier stage post partum than the rest and in fact were treated earlier than the recommended day 42. However, four of the 21 cows conceived to the timed insemination resulting in a total conception rate of 48.3 per cent.
Vet Rec 1980 Aug 23
PMID:Milk progesterone profiles and the double injection of cloprostenol in post partum beef cows. 744 99

Early stage embryos of the starfish Pisaster ochraceus exhibit one cilium per cell which is primarily involved in locomotion. SEM observations have demonstrated two types of microvilli "stage horn"-like and "finger-like" microvilli (CMs), both of which probably serve to anchor and support the hyaline layer (HL). The CMs arise from the cellular membrane a short distance from the base of the ciliary shaft and form a circle around the base of each cilium. This arrangement is found in embryos and larvae as well as in adult tissues of many other marine organisms. TEM observations of material prepared by freeze substitution has demonstrated that the HL unites the circle of CMs and forms two collars. The outer ECM collar is single and attached directly to the CMs, while the inner collar consists of multiple rings of ECM located between the cilium and the CMs. The inner collar elements are not attached to the cilium but are attached to the inner aspects of the CMs by a complex arrangement consisting of a loop of ECM and two short ECM fibers. The arrangement of the ECM of the collars could provide an excellent way to transmit the movements of the cilium to the surrounding microvilli. Although the bases of the CMs always encircle the ciliary shaft, the shafts of the CMs are seen in different positions. This suggests that the CM/ECM collar may be able to change position relative to the cilium. Confocal laser scanning microscopy demonstrates that the CMs contain phalloidin positive material which extends into a phalloidin positive region located in the apex of the cells. The CMs and apical web contain microfilaments which are probably actin and could be involved in movement of the CMs. A movable circle of CMs with their associated ECM could represent a mechanism to sense the position of the cilium and/or to define the direction and extent of the stroke.
Anat Rec 1993 Aug
PMID:The microvilli and hyaline layer of embryonic asteroid epithelial collar cells: a sensory structure to determine the position of locomotory cilia? 769 Oct 38

Natural wound formation in experimental primary neural induction has been studied by SEM and in paraffin wax sections in embryos from 0 minutes to 10 hours of re-incubation. Stage 4 host and graft embryos were removed from hen's eggs and mounted as for New culture. Graft Hensen's nodes were transplanted into "pockets" created in the host area pellucida and re-incubated for up to 10 hours. Initially the cut edges of the graft establish contact with the host ectoderm layer. After 4 hours the cut edges of the graft move from the host ectoderm to the host endoderm layer. Several small openings form in the host endoderm over the graft tissue. By 6 hours, these openings join to form a single natural wound through which the underlying graft is exposed to the external environment. At 8 hours the graft forms a head-fold and neural folds are evident. During 8 to 10 hours of re-incubation the edges of the graft which attach to the edges of the host endoderm meet in the midline and close the opening in the host endoderm; simultaneously, the graft forms a neural tube. The endodermal wounds form by cell re-arrangement and by a minor contribution from cell loss.
Anat Rec 1993 Aug
PMID:Natural wound formation: endodermal responses in experimental primary neural induction in the chick embryo. 837 93

Ampullae of Lorenzini are electrosensitive organs that, together with the olfactory organs, form the main sensory systems for foraging and navigation in skates, rays, and sharks. In sharks, these organs are mainly found on the rostral part of the head. This study describes the morphology and cytology of the ampullar system in the Oman shark, Iago omanensis, which is common in the Red Sea. The sharks were collected in the Gulf of Aqaba, Red Sea, at depths of 300-750 m, by a specially designed net. They were brought to the surface and sacrificed by an overdose of MS222, and their heads were fixed and prepared for LM, TEM, and SEM studies. The ampullae are of the polyvesicular type, and their sensory alveoli are situated on the head only and form groups enclosed in capsules of collagenous connective tissue. The dorsal side of the head features pairs of mediorostral (MRC), laterorostral (LRC), and preorbital (POC) capsules and one frontal capsule (FC), situated at the base of the rostrum in front of the eyes. The ventral side possesses only two, small mandibular (MC) capsules. The number of sensory alveoli differs in each of the capsules, and the largest group of 500 is found in the two mediorostral capsules. Each alveolus is formed by seven to nine sensory vesicles, from which a common tubule, piercing the capsule envelope, extends to a cutaneous pore. Groups of such pores form a pattern typical for Iago. A detailed description is given of the sensory epithelium, kinociliar, and microvillar cells as well as of the supporting cytological elements. The ampullae of Lorenzini in adult I. omanensis are generally similar to those of a number of other studied sharks. However, as the study shows, their number and configuration differ and form a morphological and topographic pattern typical for this species.
Anat Rec 1998 08
PMID:Distribution, morphology, and cytology of ampullae of Lorenzini in the Oman shark, Iago omanensis (Triakidae), from the Gulf of Aqaba, Red Sea. 971 80

To help assess the immunological functions of the liver peritoneum, expression and 3D-microlocalization of adhesion molecules were studied by immuno-SEM and -TEM. The peritoneal tissues of the liver obtained from lipopolysaccharide (LPS, 1.5 microg/g BW for 24 hr)-stimulated (n = 18 including nine controls) and non-stimulated mice (n = 6 including three controls) were analyzed by immunolabeling with 15 nm gold particle single-labeling analysis of ICAM-1, ICAM-2, VCAM-1, MAdCAM-1, PECAM-1, ELAM-1, and CD105 expression. In addition, 10 and 20 nm gold particle double-labeling analysis of ICAM-1 and VCAM-1 was carried out with conventional TEM and BSE (backscatter electron) imaging. Gold particles detected in the peritoneal mesothelial cells were quantified using a computer analyzer, LUZEX III. Only ICAM-1 in non-stimulated mice and both ICAM-1 and VCAM-1 in LPS-stimulated mice were expressed on the mesothelium, but no other adhesion molecules were detected in either condition. Expression of ICAM-1 was consistently about four times greater than that of VCAM-1. Each adhesion molecule was restricted to the microvilli. ICAM-1 was expressed on all microvilli and tended to form clusters of three or four molecules. On the other hand, about 24% of the microvilli expressed VCAM-1 and less clustering was seen. Double-labeling techniques disclosed that VCAM-1 and ICAM-1 were rarely closely associated, usually spaced by about 40 nm. These results suggest that microvilli of the mesothelial cell play a significant role in leukocyte migration in the peritoneal cavity, by providing the important substrates for adhesion, ICAM-1 and VCAM-1.
Anat Rec 2000 01 01
PMID:Expression of adhesion molecules relevant to leukocyte migration on the microvilli of liver peritoneal mesothelial cells. 1060 47

For understanding the immunological functions of the peritoneum, spatial localization of integrins and their ligands was studied by immuno-SEM on the peritoneal surface of mice with cecal perforation-induced peritonitis. The cecal peritoneum 24 hr after perforation was stained with specific antibodies against LFA-1, Mac-1, VLA-4, ICAM-1, VCAM-1, and fibronectin diluted with cold University of Wisconsin (UW) solution in conjunction with immuno-gold labeling. The spatial localization of those cell adhesion molecules was detected by backscatter electron (BSE) imaging with field emission scanning electron microscope (FESEM). Numerous leukocytes with diverse surface ultrastructure were observed on the peritoneal surface by FESEM. Some leukocytes were in contact with mesothelial cells, and others adhered to the exposed underlying connective tissue. The BSE imaging showed the ubiquitous distribution of Mac-1 on all membrane domains of leukocytes, i.e., cell body, ruffles, and microvilli. In contrast, predominant expressions of LFA-1 and VLA-4 were discernible on ruffles/microvilli of some leukocytes. The mesothelial cells remaining in the inflamed area expressed both ICAM-1 and VCAM-1 on their microvilli. The fibronectin was detected on presumable collagen fibers and/or fibrin over the exposed smooth muscle layer as well as on fibrin extending between leukocyte aggregation. The spatial microlocalization of integrins was clarified on the leukocytes emigrated in peritonitis, and their ligands were detected on the inflamed peritoneum.
Anat Rec 2001 10 01
PMID:Spatial distribution of cell adhesion molecules on the peritoneal surface in the cecal perforation-induced peritonitis. 1159 May 97


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