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

The Gomori aldehyde-fuchsin (AF) method for selective staining of neurosecretory substance (NSS) has been adapted to tissue previously prepared for both scanning and transmission electron microscopy (SEM/TEM). The procedure results in precise correlation of light microscopic (LM) histochemistry with SEM/TEM of the same tissue.
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PMID:Demonstration of neurosecretory substance in previously scanned specimens: adaptation of the Gomori aldehyde-fuchsin method for correlative SEM/TEM/LM histochemistry. 8 9

Fresh pullet eggs (White Leghorn strain) were incubated from 19-2ldium-gold and observed in a Cambridge S4 scanning electron microscope. Shrunken cells with intracellular yolk granules embossed on the surface are produced by the strongly hypertonic Karnovsky's fixer (Final: 2010 mOsm). Embryos fixed with modified Karnovsky's fixer (Final: 373 mOsm) possess surfaces with irregular microappendages. Swollen cells with few microappendages are observed when embryos are fixed in a hypotonic environment (Final: 250 mOsm or less). Ideal fixatives preserve a relatively flat surface, with cells bordered by smoothsurface microappendages. For adequate SEM fixation, fixative vehicle should be approximately isotonic for tissue, with aldehyde (2% or less) added to vehicle.
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PMID:Glutaraldehyde fixative tonicity for scanning electron microscopy of delicate chick embryos. 40 4

The vascularization of the rat pineal gland was investigated with, respectively, latex and resin injection preparations of the cephalic blood vessels in adult Wistar rats. From the dissection of the latex-injected and aldehyde-fixed rat brains under the stereo light microscope it was found that the arterial supply comes exclusively from separate branches of the posterior cerebral artery. The pineal area was dissected out from the resin injected and corroded specimens under the stereo light microscope and was inspected in the SEM. The supplying arteries, identified on the basis of their endothelial cell imprint patterns, were 4 to 6 in number with a diameter of 20 to 40 micron. The venous drainage consisted of 12 to 16 short veins with a diameter of 40 to 60 micron, all draining directly into the great cerebral vein and thereafter via the sinus influens immediately into the systemic venous circulation.
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PMID:The vascularization of the pineal gland (epiphysis cerebri) of the rat. 52 8

Inhalation exposure of rodents to high concentrations of acetaldehyde produces lesions in the upper respiratory tract (URT, all regions of the respiratory tract anterior to and including the larynx). Information on the inhalation dosimetric relationships for this vapor are needed for a comprehensive understanding of its inhalation toxicity. Toward this end, uptake of acetaldehyde was measured in the surgically isolated URT of the urethane-anesthetized male F344 rat under unidirectional (50, 100, 200, or 300 ml/min) and cyclic (100 ml/min) flow conditions at inspired concentrations of 1, 10, 100, or 1000 ppm. Under all flow conditions URT deposition efficiency was strongly dependent on inspired concentration. URT deposition efficiency (under cyclic flow) averaged 76, 48, 41, and 26% at 1, 10, 100, and 1000 ppm, respectively. Nasal acetaldehyde dehydrogenase activity averaged 1.2 micrograms/min. Absolute acetaldehyde deposition rates (micrograms/min) at 100 and 1000 ppm exceeded this activity by 5- to 100-fold, suggesting a possible mechanism for the reduced deposition efficiency at high concentrations. URT deposition under unidirectional flow was strongly dependent on the inspiratory flow rate. The effect of flow rate on deposition was reasonably predicted by the mass-transfer model of Aharonson et al. (J. Appl. Physiol. 37, 654-657, 1974). The uptake coefficients determined from the unidirectional flow studies were used to predict uptake under cyclic flow by integration of the model. The predicted cyclic deposition efficiencies differed from the observed efficiencies by 2.3 +/- 4.3% (mean +/- SEM), suggesting this model might provide a reasonable first approximation for acetaldehyde uptake under cyclic breathing conditions.
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PMID:Upper respiratory tract deposition of inspired acetaldehyde. 158 66

The appearance of a new acetaldehyde-induced hemoglobin fraction, HbA1ach, and the effect of alcohol consumption on it and on the ratio of HbA1ach and glycated hemoglobin, HbA1c, were studied in vivo by cation exchange liquid chromatography. The mean +/- SEM of blood HbA1ach level was 171 +/- 13.10(-3)% of total hemoglobin as measured in 34 male teetotallers. Blood HbA1ach levels of 127 social drinkers (182 +/- 6.10(-3)%) were compared with those of 72 heavy drinkers (213 +/- 8.10(-3)%, p less than 0.01), 79 alcoholics (209 +/- 6.10(-3)%, p less than 0.01) and 16 diabetics (419 +/- 28.10(-3)%, p less than 0.001). HbA1ach correlated positively with HbA1c (p less than 0.001) and negatively with HbAo (p less than 0.001). The ratio of HbA1ach/HbA1c was effective in detecting the alcohol-induced increase in the HbA1ach fraction because the ratio reduced the disturbing effect of glucose. The sensitivity of the HbA1ach/HbA1c ratio was 33% in the heavy drinker group as compared to 40% of gamma-glutamyltransferase and 24% of mean corpuscular volume. The HbA1ach fraction and the HbA1ach/HbA1c ratio seem to be valuable in detecting excessive alcohol consumption in its early phase.
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PMID:Effect of acetaldehyde on hemoglobin: HbA1ach as a potential marker of heavy drinking. 168 9

Cells cultured on transparent conductive substrates (glass coated with indium oxide) were fixed with aldehyde and osmium tetroxide and then treated with tannic acid, uranyl acetate and lead citrate. The same cell culture preparation could be sequentially studied by light microscopy (in water immersed condition), SEM (after dehydration and critical point drying) and TEM (after embedding in an epoxy resin). This method ensures the preservation of intact cell morphology, cell surface topography and intracellular structures. The treatments used render the cells conductivity and permit to carry out successfully SEM of uncoated cells cultured on conductive substrates. This method also provides a higher contrast of TEM images.
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PMID:[A method for the chemical treatment of cells for the purpose of the subsequent study of the same cell culture preparation by light, scanning and transmission electron microscopy]. 170 38

We conducted analyses of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (1Me3C-THBC) by gas chromatography-mass spectrometry (negative chemical ionization mode) to investigate its presence and the in vivo condensation between tryptophan and AcH. 1Me3C-THBC was found in the cerebellum and the cerebrum of normal rat [117.0 +/- 41.7 and 46.5 +/- 13.9 pmol/g tissue (mean +/- SEM), respectively]. The concentrations of 1Me3C-THBC and tryptophan were higher in the cerebellum than those in the cerebrum. The level of 1Me3C-THBC in both regions remained unchanged following a single oral ethanol administration alone or with cyanamide pretreatment. These data suggest that acetaldehyde is an unlike precursor of 1Me3C-THBC as a result of ethanol ingestion. 1Me3C-THBC also existed in the rat chow (282.0 +/- 24.2 pmol/g), so that most of brain 1Me3C-THBC detected in the rat brain might have originated from dietary sources. However, the possibility of a biosynthesis from tryptophan and alpha-keto acid still remained, especially after long-term ethanol treatment.
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PMID:1-Methyl-tetrahydro-beta-carboline-3-carboxylic acid is present in the rat brain and is not increased after acute ethanol injection with cyanamide treatment. 173 23

Collagen shields have been studied in the enhancement of the initial healing of epithelial defects, as an adjunct in the treatment of dry eye, and as a reservoir and delivery system for topical ocular medications. The authors used collagen shields to collect information on the numbers and types of free cells populating the normal and postoperative ocular surface. In addition, correlative microscopic techniques were used to study details of the mechanisms responsible for the dissolution of the shields when applied to the human eye. Collagen shields were applied as a bandage lens on the eyes of patients who underwent extracapsular cataract extraction (n = 10) or penetrating keratoplasty (n = 10) and on normal volunteers (n = 10). The shields were collected at the 1-day postoperative examination and fixed in aldehyde mixtures. Specimens then were processed for correlative light (LM), transmission (TEM), and scanning (SEM) microscopy. Cell accumulation was shown by SEM on both anterior and posterior shield surfaces. Cell adherence occurred primarily on the posterior shield periphery for approximately 2 mm, with the central zone relatively clean. Both LM and TEM evaluation revealed cell counts ranging from 0.066 cells/10(4) microns2 (standard deviation, +/- 0.256) in healthy eyes compared with shields placed on postoperative eyes (194.25 +/- 7.32 cells/10(4) microns2). Various correlative microscopy techniques revealed that most cells were polymorphonuclear leukocytes with a low number of other hematogenous (lymphocytes and monocytes) and exfoliated epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Collagen shields as a vehicle for collecting and studying migratory cells on human corneas. 174 Mar 59

A study was undertaken in 16 male C57BL mice to evaluate the effect of ethanol intake via the drinking water (10% v/v) on urinary-associated acetaldehyde. Eight received ethanol and 8 served as controls. Urinary-associated acetaldehyde (UAA) was measured using a fluorigenic high performance chromatographic assay. Ethanol consumption did not impair growth over the two weeks of the experiment. Following administration of ethanol, UAA increased and remained significantly elevated over levels seen in controls until ethanol administration ceased (11.3 +/- 3.6 SEM microM for ethanol-consuming mice vs. 0.69 +/- 0.33 microM for controls). Ethanol in the urine was found to interfere with the assay for acetaldehyde. However, following cessation of ethanol, acetaldehyde in urine was found to be significantly elevated in urine at 24 hours, after ethanol levels were no longer detectable. In conclusion, measurement of urinary-associated acetaldehyde discriminates ethanol-consuming from nonconsuming mice during ethanol ingestion as well as 24 hours following cessation of ethanol when ethanol levels are no longer detectable in urine. Thus measurement of urinary acetaldehyde may be a useful marker for monitoring ethanol intake.
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PMID:Studies of urine-associated acetaldehyde as a marker for alcohol intake in mice. 178 20

Muscle spindles in the tenuissimus muscle of mature golden Syrian hamsters were examined by conventional and high-resolution scanning electron microscopy (HRSEM). For conventional SEM, entire muscles were first fixed in 2.5% buffered glutaraldehyde. Spindles were then isolated with a dissecting microscope under darkfield illumination and postfixed in 1.0% OsO4. Some spindles were treated with 8 N HCl at 60 degrees C to clearly expose intrafusal fiber surfaces once the outer capsular sheath was mechanically disrupted. Preparation for HRSEM included aldehyde/osmium fixation and freeze-cleavage in liquid N2. The cytosol and certain cellular elements were also selectively extracted by immersion in 0.1% OsO4 for varying time intervals. In these preparations, the capsular sleeve showed a multilayered pattern of vesicle-laden cells with variant surface topography in different regions, including filopodia and small bristle-like surface-projections. An interlacing three-dimensional network of collagen fibrils intervened between the capsular lamellae. Within the spindles, sensory and fusimotor nerve endings closely adhered to the outer surfaces of intrafusal fibers. Sensory nerve terminals were enveloped by a prominent external lamina, and those that were cleaved open contained a plethora of elongated mitochondria that ran parallel with the longitudinal axis, along with vesicles, axoplasmic filaments, and lysosomes. Multiple adhesion sites between the sensory nerve membrane and the underlying sarcolemma of the intrafusal fiber were also observed in select regions. Fusimotor nerve endings were covered externally by processes of Schwann cells and their axoplasm was filled with a multitude of cellular organelles and synaptic vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Muscle spindle ultrastructure revealed by conventional and high-resolution scanning electron microscopy. 186 95


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