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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Whole retinae of 4- to 10-day-old chick and quail embryos were spread on membrane filters and kept in culture for up to 4 days. Axon growth during culture was demonstrated by silver staining, anterograde labeling of fibers with RITC, time-lapse recording, and SEM. Fiber growth was observed in specimens from chick embryos up to 7 days old, with a growth maximum at E6 and from quail embryos up to E6 with the maximum at E5. Newly growing axons followed the optic fiber pattern already existing and, like axons in vivo, grew predominantly toward the optic fissure. Directional and orientational adaptation of newly growing axons to the preexisting fibers increased with the donor age. Retinae from donors up to E5 in chick and up to E4 in quail showed a high proportion of axons which crossed the optic fissure during the culture period and invaded the opposite retinal fiber layer. These fibers showed a correct radial orientation while growing in the opposite direction to normal. Likewise, in cultures from these young donors some fibers grew out initially in the diametrically opposite direction to normal toward the tissue periphery. Since all of the wrongly directed axons grew at the same rate as normal and adapted correctly to the already formed axon pattern, this suggests independent signals for the direction and orientation of growing fibers. Treatment of mounted retinae with collagenase or trypsin removed the vitreal retinal surface, leaving the existing axon pattern intact. Subsequently, new axons grew profusely in culture, but lost both their orientational and directional characteristics.
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PMID:Axon growth in embryonic chick and quail retinal whole mounts in vitro. 620 Mar 72

To evaluate the role of nonsteroidal, follicular fluid proteins in folliculogenesis, the 10-55% saturated ammonium sulfate fraction of pooled human follicular fluid was dialyzed against 0.025 M Tris/HCl (pH 7.5) using 10,000 molecular weight exclusion membranes, then passed through agarose immobilized textile dye. Activity was determined by test fraction inhibition of human menopausal gonadotropin (2 U human LH/FSH . day), induced ovarian weight, and serum estradiol increase in hypophysectomized, diethylstilbesterol-treated, 25-day-old female rats. Specific inhibition (89 +/- 6.8% SEM) of ovarian weight increase was found in the material (2 ml) eluted from an Orange A column with KCl (1.5 M, pH 6.8). Inhibitory activity of the Orange A-bound material, which eluted through a standardized Sephadex G-50 column, corresponded to a molecular weight of 13,000-25,000. Isoelectric focusing on a Sephadex G-15 support bed or ampholyte displacement chromatography of Orange A bound material demonstrated inhibitory activity at pH 3.5-4.5 and 6.5-7.0. No demonstrable activity was found in similar fractions eluted through a Concanavalin A-Sepharose 4B column before or after addition of alpha-methyl-D-mannoside (2 M, pH 7). When active fractions were heated (56 C, 1 h) or exposed to trypsin (10 mg/100 ml), activity was lost. When aliquots of the saturated ammonium sulfate-extracted, dialyzed, Orange A-bound eluent were separated by high performance liquid chromatography using gel exclusion columns, activity in the bioassay was recovered in the 13,000-35,000 molecular weight range. Although confirmatory data await further studies, it is tempting to speculate that this protein(s) may be an important inter- and/or intraovarian regulator of follicular response to gonadotropins.
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PMID:Identification of proteins in pooled human follicular fluid which suppress follicular response to gonadotropins. 640 Nov 85

Techniques applied in SEM studies of a solid organ such as the kidney are reviewed. The tissue can be prepared by razor sectioning, ethanol cryofracture and ultraplanning of polyethylene glycol embedded tissue. Tissues embedded in paraffin can also be used. Glomeruli and tubuli can be isolated from renal biopsies. A new procedure for tubular isolation is based on sequential digestion by trypsin, pepsin and Pronase E. SEM examination has proved useful in a number of renal diseases, such as glomerular diseases, hypertensive renal disease, an tubular diseases, including medullary cystic disease, adult polycystic disease, and acute tubular necrosis. Particularly in human acute tubular necrosis, SEM was helpful. SEM has also contributed to the study of the physiologically important basal-lateral surfaces of human, dog, rat, rabbit and frog renal tubules, and in particular allowed the elucidation of patterns of processes on the basal-lateral surfaces of proximal S1, S2, and S3 tubular segments, thin limbs, distal ascending and convoluted limbs and collecting ducts in human tubules.
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PMID:The complementary role of scanning electron microscopy in renal pathological diagnosis. 641 8

In this paper the ultrastructural features of the epithelial-mesenchymal interface in mandibular processes of embryonic chicks have been examined using scanning electron microscopy. Mandibular epithelium is required for the mesenchyme to differentiate as osteoblasts and to deposit the membrane bones of the mandible. The surface morphology of the epithelium changes from the lateral to the medial face of the mandible from rounded cells, each with a central cilium to flattened cells with numerous microvilli. Treatment with trypsin and pancreatin was used to digest the basal lamina so as to separate epithelium from mesenchyme. This exposed a thick, fibrillar basement membrane (reticular lamina), which was thicker underlying the caudal epithelium than under the cephalad epithelium. Addition of collagenase to the trypsin/pancreatin solution degraded some of the basement lamella, especially that underlying epithelium on the caudal portion of each mandibular process. Selective degradation of basement lamella is postulated as one means of regulating inductive epithelial-mesenchymal interactions. EDTA was used to isolate basal laminae on mandibular mesenchyme. SEM was used to confirm the integrity of the basal lamina, its structure, and its association with overlying epithelial cells and underlying basement lamella.
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PMID:An SEM analysis of the epithelial--mesenchymal interface in the mandible of the embryonic chick. 673 22

The neural retina of avian embryos was spread on a membrane filter and cut in any desired orientation. Strips cut across the retina of 4- to 7-day chick or 3- to 6-day quail embryos were explanted onto collagen gels. Vigorous neurite outgrowth was seen for about 3 days, by which time many neurites were 3 mm long. Horseradish peroxidase (HRP) labeling showed that the cells producing the neurites were large and formed a layer near the inner limiting membrane, indicating that the neurites in vitro were axons of retinal ganglion cells. The size of the neurite population and the regions from which neurites emerged varied with the donor age, while most neurites sprouted from the side of the explant formerly closest to the optic fissure. This pattern closely resembled that of axon growth in the normal retina, as revealed by SEM, silver staining, and HRP labeling. Mitotic inhibitors (Ara-C and FUdR) did not alter the neurite outgrowth. Pretreatment of retinae with trypsin or collagenase did not disorganize axons at the time of explanation, but tended to equalize neurite emergence on each side of the retinal strips. We suggest that microenvironmental factors, especially the enzyme-labile inner limiting membrane, are important for axon guidance in the retina.
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PMID:Oriented axon outgrowth from avian embryonic retinae in culture. 682 32

Serum immunoreactive trypsin (IRT) under basal conditions and after pancreatic stimulation with secretin was studied in 10 patients with type IV hyperlipoproteinemia (HLP) and in 10 control subjects. No significant difference was observed between basal values of the two groups (p = NS). The increase of serum IRT was already significant 5 minutes after secretin administration (p < 0.01) and persisted with significance for one hour in both groups. The integrated trypsin output (ITO) was significantly greater in type IV HLP than in controls (510.3 +/- 17.8 and 72.2 +/ 17.6 respectively, mean +/- SEM, p < 0.0125). Only 2 (20%) of 10 patients with HLP had an ITO in the range of the controls. No significant correlation was found between ITO and triglyceride levels (p = NS). The response of serum IRT to secretin in HLP patients appears comparable to that observed in alcoholics and in patients with chronic pancreatitis with mild to moderate exocrine dysfunction, in whom there may be an abnormal regurgitation of trypsin-like material into the blood stream after secretin stimulation, probably due to an obstruction to pancreatic secretory flow. A similar obstructive mechanism may be hypothesized also in patients with HLP, but no data concerning the exocrine pancreatic secretion and the histological features of the pancreas are available to confirm this hypothesis.
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PMID:Serum immunoreactive trypsin in type IV hyperlipoproteinemia. 693 55

Serum trypsin concentrations within the portal venous system have been measured in man during transhepatic portal venography in an attempt to determine its source. In eight experiments, mean serum trypsin concentration at the splenic hilum was 180 +/- 25 ng/ml (mean +/- SEM). Trypsin concentration in the rest of the splenic vein was not significantly different. The mean concentrations in the portal vein (210 +/- 32 ng/ml) and within the superior mesenteric vein (233 +/-- 29 ng/ml) were, however, significantly higher than at the hilum (P less than 0.05). Following cholecystokinin-pancreozymin (CCK-PZ) and secretin stimulation, marked increases in serum trypsin concentration were seen within the portal vein (two patients) and deep within the superior mesenteric (two out of three patients). We conclude that circulating serum trypsin is derived, at least in part, from intestinal reabsorption.
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PMID:Origin of circulating serum immunoreactive trypsin in man. 697 4

Artificial splits made in rat femoral condylar articular cartilage have been studied by SEM. Three types of split have been described; non-layered, unidirectional layered and multidirectional layered. The frequency of each type of split varies in the different regions of the condyle. Deformation and crack propagation are features of layered splits and the latter are often accompanied by exposure of fibres. The fibre pattern over the articulating surface of the rat femoral condyle, revealed by trypsin or NaOH treatment, has been determined and a correlation found between this pattern and the orientation of splits previously observed by ILM. The influence of fibre arrangement on split production is discussed and consideration given to other factors, such as mechanical stress, chondrocyte distribution or PG concentration gradients, which may determine both characteristic patterns. Further evidence is presented of the value of the pin prick method as a technique for exploring the nature of normal and abnormal articular cartilage.
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PMID:Fine structure of artificial splits in femoral condylar cartilage of the rat: a scanning electron microscopic study. 699 39

The inflammatory cell composition of pleural or ascitic effusion fluids from 13 patients with malignant disease and 8 patients with benign disease was analyzed. The macrophage content in the effusions was 4.1 x 10(5) +/- 1.3 cells/ml (mean +/- SEM), with large variation (range 0.1 - 27.9 x 10(5) cells/ml) among patients. Major blood cell contamination was excluded by the finding of low red blood cell/nucleated cell ratios in the effusions. Effusion macrophages were isolated by Ficoll/Isopaque centrifugation and plastic adherence. Monolayers of > 90% alpha-napthyl-esterase-positive and/or phagocytic cells were produced in most experiments. Adherent effusion cells incorporated low amounts of methyl-3H-thymidine (methyl-3H-TdR). Most cells in DNA-synthesis were removed by trypsin, indicating that they were not macrophages. Lymphokine supernatants induced increased methyl-3H-TdR incorporation in adherent cells in 3 of 8 experiments, and microscopic proliferation of phagocytic cells was evident in one experiment. Endotoxin and Corynebacterium parvum reduced adherent cell DNA-synthesis slightly. Effusion macrophages ingested more 125I-labelled Candida albicans than peripheral blood monocytes. The ability to degrade ingested Candida and the cell adherence after phagocytosis were found to be greater in the macrophages than in monocytes. Effusion macrophages with monocyte-like, undifferentiated appearance differentiated like monocytes in vitro. Further in vitro differentiation of macrophages with more differentiated appearance often seemed to be blocked, the cells dying gradually after 4-8 days in vitro.
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PMID:Structure and function of human effusion macrophages from patients with malignant and benign disease. 1. Isolation, morphology, proliferation and phagocytosis. 700 80

High-affinity binding of melatonin to crude membrane preparations of bovine pineal gland was examined by a rapid filtration procedure through Whatman GFB paper. Maximal melatonin binding was attained in 60 min at 37 degrees C, in 2 h at 25 degrees C and in 5 h at 0 degree C; at 25 and 37 degrees C it was 36 and 42% of that at 0 degree C. Specific binding was thermolabile and decreased following incubation with trypsin; it was also pH dependent, the maximum being observed at physiological pH. Melatonin binding was inhibited by the addition of monovalent or divalent ions to the incubation buffer. Subcellular fractionation studies indicated that 39 and 50% of binding was located in the pellets at 900 and 27,000 g whereas 11% was detected in the microsomal pellet. Scatchard analysis revealed a single population of binding sites with Kd = (7.0 +/- 1.5) 10(-7) M (mean +/- SEM, n = 4); binding site concentration ranged from 185 to 356 fmol/mg of protein. When various melatonin analogues were tested for their ability to inhibit (3H)-melatonin binding, the following Ki values (10(-7) M), were obtained: N-acetyl-serotonin 120, serotonin 130, 2-methyl indole 154, 5-hydroxytryptophol 218, 5-methoxytryptamine 266, 5-methoxytryptophol 660, tryptamine 1,740, 5-hydroxyindole acetic acid 3,455, 5-methoxyindole acetic acid 12,690, 5-hydroxytryptophan 13,600, and 6-hydroxymelatonin 55,550. Those results suggest that melatonin receptors may be present in the pineal gland.
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PMID:Binding sites for melatonin in bovine pineal gland. 722 76


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