[Photography of extracted teeth in a high voltage high frequency field (prelimanary report)].
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Decalcification Technique↗
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High voltage electron microscopy 1977. Proceedings of the Fifth International Conference on High Voltage Electron Microscopy.
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Congresses as Topic↗
Human nervous system tumors. Observations by high voltages electron microscopy.
Thick sections (0.5--2 mu) of biopsies from human nervous system tumors (Schwannoma, ependymoma, medulloblastoma), fixed in aldehydes followed by osmium, and stained with uranyl acetate and lead, have been studied at 2.5 MV, and compared to thin sections of the same material observed by ordinary low voltage electron microscopy. High voltage electron microscopy permits direct observation of cell fine structure in three dimensions, including the spatial relations of organelles. Details of contours of nuclear envelopes, shapes of mitochondria, fine aspects of the structure of cell surfaces and processes, such as the flat sheet-like and irregular cylindrical processes of Schwannoma cells, the small projections and ridges on their surfaces, and microvilli and cilia of ependymoma cells, and other features have been observed. These initial observations demonstrate the applicability of high voltage electron microscopy to further study of neural neoplasms.
Adolescent↗
Skull injuries caused by high voltage electricity.
Four cases by high voltage electricity are reported. Particular interest is taken in describing initial conservative treatment of injuries where the entrance of the current has been through the head, followed by surgical excision and flap surgery. This procedure had an uneventful postoperative course. Other methods comprising an earlier excision and revitalizing flap coverage over the necrotic bone thereby avoiding later bone grafting are being discussed and may be preferable. A decrease in high voltage injuries has been noticed during the last ten-year period compared to earlier data (5.5% down to 1.4%). This may well be partially explained by improved precautionary measures, but children are still prominent among the injured. All the children were injured while playing around railroad areas.
Electric Injuries↗
Comparison of active zones in spinal cord of anesthetized and unanesthetized rats: a high voltage electron microscope study.
High voltage electronmicroscopy was applied to the study of presynaptic nerve terminals and specifically the arrangement and staining properties of synaptic vesicles in and around the active zone. The zinc iodideosmium tetroxide technique was used for the impregnation of neuropil derived from the spinal cord of anesthetized (40 mg/kg pentobarbital sodium) and unanesthetized rats. Under optimal conditions of section thickness and tilt angles stereoscopic views of a paracrystalline lattice arrangement of synaptic vesicles could be ascertained. The ZIO affinity was significantly higher in synaptic vesicles of the anesthetized as compared with the unanesthetized preparations.
Animals↗
Bovine olfactory and nasal respiratory epithelium surfaces. High-voltage and scanning electron microscopy, and cryo-ultramicrotomy.
High-voltage transmission electron microscopy and cryo-ultramicrotomy together with scanning electron microscopy and some conventional transmission electron microscopy of ultrathin sections have been applied to the mucous surfaces of bovine olfactory and respiratory epithelia. Distal segments of olfactory cilia tend to run in parallel and could be followed over distances up to about 30 micrometer using high-voltage electron microscopy. This technique and scanning electron microscopy showed that on average 12--13 of such cilia could be observed per nerve ending. After correction for obscured cilia this number becomes about 17. High-voltage micrographs and micrographs made from sections prepared with a cryo-ultramicrotome showed the presence of electron-lucent pockets inside the olfactory mucus. The latter technique also showed that the mucus itself is not fibrous, but rather a continuum varying in electron density. The mucus layer contains various granular structures. Ciliary and microvillar membranes appear thicker with cryo-ultramicrotomy than when the sections are prepared with conventional techniques. The cores of the axonemal microtubules in olfactory as well as in respiratory cilia are darkly stained with this technique. Vesicles present inside the nerve endings are also darkly stained. Dimensions and some other numerical values of interest in olfaction are presented.
Animals↗
Guinea-pig keratinocytes and melanocytes in tissue culture: scanning, transmission and high voltage electron microscope observations.
Keratinocytes and melanocytes cultured from guinea-pig epidermis were studied with scanning, transmission and high voltage electron microscopy to characterize the surface and internal morphology. Keratinocytes exhibited contact-inhibition and a range of surface structures consistent with cell-cycle dependent changes. Stereoscopic analysis of high voltage electron micrographs indicated regular oval nuclei with nucleoli at different depths, while thin sections revealed local channels in the nuclei. Secondary cultures differed from primary cultures in the disorder of the microfilaments, in the failure to form desmosomes, and in the failure of melanocytes to persist in culture. The beaded surface of melanocytes was indicative of underlying melanosomes that were seen in high voltage micrographs. Melanocytes were rounded with moderate ruffles or were dendritic with ruffles on the termini. These findings are discussed in relation to the observational techniques and in relation to modes of locomotion of and pigment transfer to epidermal cells.
Animals↗
High-voltage pulsed galvanic stimulation: effects of frequency of current on blood flow in the human calf muscle.
1. Twelve healthy subjects received high-voltage pulsed galvanic stimulation (115-475 V d.c.) delivered in separate treatments of 2, 32 and 128 pulses/s for 10 min at the subject's maximum tolerable voltage while calf muscle blood flow was measured by non-invasive Whitney strain-gauge venous occlusion plethysmography. 2. The high-voltage pulsed galvanic stimulation was administered with negative polarity by an intermittent mode of 30 s on, 30 s off. Measurements of calf muscle blood flow were made during each 30 s period when the stimulus was off. The effect of one 30 s maximum isometric contraction of the calf muscles on blood flow was used as a standard for evaluating the effectiveness of high-voltage pulsed galvanic stimulation on calf muscle blood flow. 3. Significant (paired t-tests; P less than 0.05) increases in calf muscle blood flow over the preceding baseline levels occurred for the isometric contraction (322%) and for frequencies of 2 pulses/s (33.5%) and 128 pulses/s (13.36%), but not for a frequency of 32 pulses at which calf muscle blood flow increased in only six of 12 subjects. The mean increases in calf muscle blood flow at 2 and 128 pulses/s represented 11.63% and 4.0%, respectively, of that resulting from the isometric contraction. 4. A clear positive correlation between voltage level and the magnitude of increase in calf muscle blood flow was demonstrated but differed for each frequency used.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Early decompression fasciotomy in the treatment of high-voltage electrical burns of the extremities.
Based on a knowledge of electropathophysiology, a recommended treatment has been proposed for the management of extensive high-voltage electrical burns. Early, aggressive, surgical intervention consisting of adequate decompression fasciotomy and wound debridement has been emphasized as the first line of treatment. Frequent redebridements under general anesthesia are important to the preservation of viable tissue. Early coverage procedures or attempts at primary closure following decompression are contraindicated in high-voltage injuries. This method of treatment in eight cases of high-voltage, electrical injury has preserved viable tissue, decreased the incidence of fatal sepsis and renal shutdown, decreased patient morbidity, and generally facilitated patient rehabilitation.
Adult↗
Resolution of antibiotic mixtures in serum samples by high-voltage electrophoresis.
The use of high-voltage electrophoresis and bioautography for the separation mixtures of antibiotics received in clinical serum samples is described. The electrophoretic characteristics of 39 antibiotics are given as is the accuracy of the method for quantitating three antibiotics. In screening 189 consecutive serum samples submitted for routine antibiotic assay, undisclosed antibiotics were revealed by the technique in 35.
Aminoglycosides↗
Continuous, generalized, high-voltage fast activity and FIRDA in two children.
The EEG pattern of continuous, generalized, high-voltage fast rhythms without any reaction to eye-opening/closure, photic stimulation, or the sleep-awaking cycle was previously reported to be characteristic of infantile neuroaxonal dystrophy (INAD). However, we have observed such fast activity in one child with INAD and one with Menkes' kinky-hair syndrome. They both exhibited severe psychomotor disturbance, and their EEGs also included "frontal intermittent rhythmic delta activity (FIRDA)," a nonspecific EEG finding suggestive of organic encephalopathy. Since the continuous, generalized, high-voltage fast activity had features suggestive of spindles in both children, this EEG pattern is thought to actually represent "extreme spindles," and nonspecifically to indicate widespread organic brain damage.
Cerebral Cortex↗
High-voltage electron microscopy of extracellular fibrillogenesis.
High-voltage electron microscopy was employed to observe developing extracellular connective tissue elements in the cervical perinotochordal and perivertebral regions in the chick embryo from 2 through 15 days' incubation. During days 2 and 3, small (10 nm) and large (18-20 nm) microfibrils surrounded the notochord, becoming evident around fibroblast-like cells in day 4. Amorphous material, globular granules and microfibrillar bundles were present at this time. Microfibrillar length increased as did the total population of microfibrils. At four days microfibrils 3-5 nm in diameter arose in all directions from globular granules. During day 9 and thereafter to day 15, microfibrillar diameters increased. This growth formed unit collagenous fibrils 30 nm in diameter or greater. Axial periodicity became evident at day 14. Small microfibrils appear to be composed largely of glycoproteins and do not contain a significant amount of collagen. The globular granules and associated filaments are probably proteoglycans. The amorphous material is believed to provide molecular collagen to developing fibrils. Large microfibrils and unit collagenous fibrils contain significant amounts of molecular collagen.
Animals↗
Determination of exposure to electric fields in extra high voltage substations.
Electrophysical effects related to extra high voltage are surveyed for the determination of the exposure of personnel to electric fields in substations. It is concluded that the electric field strengths and the electrical discharges to the personnel are the important electrophysical factors. Instruments for measuring the field strength at grounded surfaces and at nonzero potentials were constructed. Results are presented of measurements with these instruments in substations. A dummy was used for the measurement of the distribution of capacitive currents to a man. The dummy can also be used for measuring the effectiveness of special shielding clothes.
Accidents, Occupational↗
Localisation of the [32P]IP3 binding site on human platelet intracellular membranes isolated by high-voltage free-flow electrophoresis.
This study reports the localisation of the [32P]IP3 binding site on highly purified membrane fractions prepared using high-voltage free-flow electrophoresis. Binding studies on mixed membranes, carried out at 4 degrees C, revealed a binding site with a Kd = 86 nM and beta max = 5.3 pmol/mg protein. The binding was potently inhibited by heparin. High-voltage free-flow electrophoresis was used to further purify surface and intracellular membranes. The intracellular membranes showed a 5-fold enrichment of binding sites with respect to the parent mixed membranes with the same Kd (80 nM), but the surface membranes showed an absence of binding activity. The results indicate the localisation of the IP3 receptor on highly purified intracellular membranes.
Binding Sites↗
The primate median eminence. II. Correlative high-voltage transmission electron microscopy.
The ultrastructure of the normal median eminence of the male rhesus monkey (Macaca mulatta) is described using high-voltage electron microscopy. Surface specializations of ependymal cells lining the infundibular recess included cilia, apical extrusions, and microvilli. Supraependymal cells were predominantly macrophage-like, but examples of lymphocytic types were also seen. Tanycytes had long, branching, basal processes filled with numerous microtubules, some lipid droplets, and granules. The zona interna was composed of large unmyelinated neurosecretory fibers. A few myelinated fibers were also seen, but their character as neurosecretory fibers could not be established. The zona externa was composed of densely-packed profiles of neuro secretory fibers of small diameter, was well-vascularized and contained the terminations of tanycytes. Perivascular glial cells, vesiculated elements, pituicytes, and cellular elements common to connective tissue were observed. The intricate relationships between both the cellular and fibrous elements of the median eminence can be appreciated with the capability of high-voltage electron microscopy to discern ultrastructure in sections 10 times thicker than those used for low-voltage electron microscopy. The median eminence of this primate species has an ultrastructural organization similar to that described for most other species.
Animals↗
Continuous alpha 2-adrenoceptor blockade by atipamezole decreases neocortical high-voltage spindle activity in rats.
The present study investigates the effects of a subchronic continuous infusion of atipamezole, a potent and selective alpha 2-adrenoceptor antagonist, on neocortical high-voltage spindle (HVS) activity in rats. Six days' subcutaneous infusion of atipamezole (0.125 mg/kg per h) with osmotic minipumps decreased HVS activity significantly. The HVS activity-decreasing effect of atipamezole persisted at the same level throughout the infusion. A single subthreshold dose of an alpha 2-adrenoceptor agonist, guanfacine (0.001 mg/kg i.p.), did not affect HVS activity either before or after the continuous atipamezole treatment. The central alpha 2-adrenoceptor blocking effect of atipamezole (0.1 mg/kg per h s.c.) was confirmed to be at the same level after one, three or seven days' infusion, as assessed by measuring the antagonism of detomidine-induced mydriasis in the rat. The serum concentration of atipamezole (0.1 mg/kg per h s.c.) increased slightly from day 3 (37 +/- 11 ng/ml) to day 7 (45 +/- 4 ng/ml). In conclusion, the results of the study suggest that the suppressant effects of atipamezole on neocortical high-voltage spindle activity are preserved during subchronic continuous treatment. In addition, alpha 2-adrenoceptor blockade, as measured in the rat mydriasis model, persists at the same level during subchronic infusion.
Adrenergic alpha-Antagonists↗
Enrichment of the murine natural killer (NK) and mitogen induced cellular cytotoxicity (MICC) cells using preparative free-flow high voltage electrophoresis.
A procedure using preparative free-flow high voltage electrophoresis is described for the fractionation of murine spleen and bone marrow cells so as to obtain cell subpopulations that are either enriched in or depleted of "natural killer" (NK) cells and "mitogen-induced cellular cytotoxicity" (MICC) effector cells. A nearly three fold enrichment in the NK and MICC activities of spleen cells was achieved. The enrichment in these cells could be further increased if the phagocytic cells were removed prior to electrophoresis. When bone marrow cells were fractionated a two and a half fold increase of NK activity, and a one and a half fold enrichment of MICC activity was achieved. In both cases, other fractions were nearly devoid of NK and MICC activity. The cell recovery after electrophoresis averages 70% of the cells applied, and at least 90% of these cells were viable. MICC and NK effector cells could not be separated to a useful extent electrophoretically but were found to be separable using Sephadex C-10 gel filtration columns. The MICC but not the NK cells were retained on these columns.
Animals↗
Decoupled Synthesis Pathway via Precursor Functionalization Stabilizes High-Voltage Nickel-Based Cathodes.
Nickel-based layered cathodes are promising candidates for high-performance, high-energy lithium-ion batteries, yet their high-voltage application is jointly limited by synthesis-inherited structural defects and an unstable lattice oxygen framework. Here, we show that both limitations can be overcome by decoupled synthesis pathway (DSP) via La/Nb oxalate functionalization of the Ni0.6Co0.1Mn0.3(OH)2 precursor. Unlike the conventional coupled synthesis pathway (CSP) where precursor dehydration and Li2CO3 decomposition overlap in temperature, the DSP introduces a low‑temperature decomposition of La/Nb oxalates at 200°C, which effectively avoids localized contact between the precursor and Li2CO3 and shifts Li2CO3-related reactions to high temperatures. This allows sequential precursor dehydroxylation, rock‑salt (RS) intermediate formation, and layered‑phase transformation over a broad temperature window. The resulting LiNi0.6Co0.1Mn0.3O2 cathode with La/Nb functionalization (NCM-LN) features a uniform surface LaNiO3 perovskite heterostructure and a Nb‑doped layered bulk with suppressed RS and spinel defects. Consequently, under 4.5 V operation (vs. Li+/Li), NCM-LN exhibits homogeneous Li+ (de)intercalation, and a stabilized oxygen framework. In graphite||NCM-LN full cells, NCM-LN retains 80.1% of its capacity after 2000 cycles at 1C, substantially outperforming the pristine cathode. This decoupling strategy is broadly effective across various Ni‑based systems, providing a generalizable route toward high‑energy, long‑life cathode materials.
decoupled synthesis pathway↗