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  • 1
    Electronic Resource
    Electronic Resource
    Mössbauer study of perovskite oxides for oxidative coupling of CH4 and absorption of CO2 (1997)
    Springer
    Czechoslovak journal of physics 47 (1997), S. 517-522 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Perovskite oxides, (Ba0.95Ca0.05) (Co1−x Fe x ) O3−δ, are prominent materials for oxidative coupling of methane and for CO2 absorption at high temperature, and these oxides before and after treatment in CH4 and CO2 atmosphere were analysed by Mössbauer spectroscopy. The perturbation of microstructure by substitution of Ba sites with Ca, and the electron transfer of mixed valences in Fe and Co ions with the formation of oxygen vacancies at high temperatures, are considered to contribute strongly to the selectivity of CH4 coupling and the rapid absorption of CO2 at high temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021251221571
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  • 2
    Electronic Resource
    Electronic Resource
    Fine structure of the semicompact formation of the nucleus ambiguus of the rat (1997)
    Springer
    Anatomy and embryology 196 (1997), S. 465-476 
    Details
    ISSN: 1432-0568
    Keywords: Key words Pharyngeal motoneuron ; Cytoarchitecture ; Retrograde tracing study ; Swallowing ; Synaptology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We investigated the fine structure of the semicompact formation of the nucleus ambiguus (AmS), which was identified by retrogradely labeled pharyngeal (PH) motoneurons. When cholera toxin subunit B-conjugated horseradish peroxidase was injected into the lower pharyngeal muscle, many retrogradely labeled PH neurons were found throughout the AmS. Besides the PH neurons, two types of neurons were recognized in the AmS: unlabeled medium-sized neurons and unlabeled small neurons. The PH neuron was large (27.6 × 44.1 μm) and polygonal, and contained many Nissl bodies and well-developed cell organelles with a prominent spherical nucleus. The medium-sized neuron was dark and oval (19.3 × 33.2 μm), and contained many free ribosomes and much swollen rough endoplasmic reticulum with a distorted oval nucleus. The small neuron was spindle-shaped (12.3 × 20.2 μm), and had poorly developed cell organelles with an irregularly shaped nucleus. The average number of axosomatic terminals in a sectional plane was largest in the PH neurons (32.8), smaller in the medium-sized neurons (23.1), and smallest in the small neurons (6.3). The number of axo-somatic terminals containing round vesicles (Gray’s type I) was almost equal to that of terminals containing pleomorphic vesicles (Gray’s type II) in the PH neuron, and slightly smaller in the small and the medium-sized neurons. About 60% of the axodendritic terminals were Gray’s type I, and 40% were type II. These results indicate that there are two different types of interneurons besides the PH motoneurons in the AmS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290050114
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  • 3
    Electronic Resource
    Electronic Resource
    Absence of apoptosis in somatotropinomas treated with octreotide (1997)
    Springer
    Acta neurochirurgica 139 (1997), S. 851-856 
    Details
    ISSN: 0942-0940
    Keywords: Apoptosis ; bromocriptine ; octreotide ; somatotropinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Octreotide is a potent agonist of somatostatin that lowers the serum level of growth hormone (GH), and reduces the size of somatotropinomas. However, the detailed mechanism of shrinkage of this tumour is not known. We, therefore, evaluated 11 patients with somatotropinomas who were treated with octreotide 300 μg/day for 2–5 weeks to observe the morphological changes in the tumour using electron microscopy and the immunocytochemical study of apoptosis using polyclonal anti-single stranded DNA. Findings were compared with those obtained with bromocriptine treatment (10 mg/day, 2 weeks) of 5 patients with somatotropinomas, and 11 patients who received no preoperative treatment (control group). The octreotide group showed neither increase in stromal tissue nor cell death. The size of tumour cells appeared to be slightly reduced. No typical apoptotic bodies were seen on the electron micrographs. The apoptotic index in the octreotide group (0.40 ± 0.60%; mean ± SD) resembled that in the control group (0.81 ± 0.79%). In contast, the bromocriptine group showed some cell death and an increase in stromal tissue. The bromocriptine group also showed the apoptotic index which (20.1 ± 14.8%) was significantly higher than that of the control group (0.81 ± 0.79%). Thus, octreotide did not induce apoptosis in somatotropinomas despite the presence of tumour shrinkage. Because of the lack of fibrosis observed in the octreotide-treated tumours, the preoperative administration of octreotide may help to improve the outcome of the transsphenoidal operation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01411403
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  • 4
    Electronic Resource
    Electronic Resource
    Loss and apoptosis of smooth muscle cells in intracranial aneurysms studies with in situ DNA end labeling and antibody against single-stranded DNA (1997)
    Springer
    Acta neurochirurgica 139 (1997), S. 469-475 
    Details
    ISSN: 0942-0940
    Keywords: Aneurysm ; anti-single-stranded DNA antibody ; apoptosis ; DNA fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pathological specimens were collected from 14 unruptured and 13 ruptured aneurysms at the time of clipping and studied in order to assess the underlying mechanism of rupture by investigating degeneration of the aneurysmal wall and possible involvement of apoptosis. Immunohistochemistry with anti-actin antibody showed few smooth muscle cells in the ruptured aneurysms and replacement of the muscularis layer by a fibro-hyalin tissue. However, at least one layer of smooth muscle cells was clearly observed in the unruptured aneurysms. Thus, smooth muscle cells in the wall of the ruptured aneurysms were much more degenerated than those in the wall of unruptured aneurysms. In addition, unruptured aneurysms with an angiographically smooth wall showed well-layered positive staining for anti-smooth muscle actin antibody while those with irregular shapes rarely reacted. We found, for the first time, evidence of DNA fragmentation in the aneurysmal wall. Apoptotic bodies were detected by means of a terminal transferase (TdT)-mediated dUTP biotin nick end labelling technique (TUNEL) and an anti-single-stranded DNA antibody in 54% (7/13) of the ruptured aneurysms. In contrast, apoptotic bodies were found in only 7% (1/14) of the unruptured cases. These results suggest that apoptotic cell death might be involved in the rupture of aneurysms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01808885
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  • 5
    Electronic Resource
    Electronic Resource
    Detection of replicative intermediate with closed terminus of Bombyx densonucleosis virus (1997)
    Springer
    Archives of virology 142 (1997), S. 393-399 
    Details
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary. Two kinds of Bombyx densonucleosis virus (BmDNV), BmDNV-1 and 2, have been isolated from sericultural farms in Japan or China. These viruses are classified into the family Parvoviridae because of the small spherical virus particle containing a single-stranded linear DNA genome. Recent studies on the genome structure of these viruses suggested that BmDNV-2 was a new type of virus with unique replication mechanism, though that of BmDNV-1 was similar to parvoviruses. However, details about the replication mechanism of BmDNVs have not been reported so far. Here, in order to elucidate the difference on replication mechanism between BmDNVs and parvoviruses, we analyzed the structure of the replicative intermediate (RI) of BmDNV DNAs by CR using specific primers designed for detection of RI with closed terminal structure (RI-CT) which is expected to be formed by replication with self-priming mechanism. PCR using the DNA from the cells infected with BmDNV-1 could detect the expected DNA fragment, showing the existence of RI-CT. On the other hand, no fragment could be amplified from the virion DNA of the BmDNVs and the DNA extracted from BmDNV-2-infected cells, respectively. These observations strongly suggested that the BmDNV-1 replicates with the “self-priming and hairpin-transfer” mechanism similar to the human parvoviruses, while BmDNV-2 does not.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007050050085
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  • 6
    Electronic Resource
    Electronic Resource
    An animal study on the bone behaviour of Ca–P-coated implants: influence of implant location (1997)
    Springer
    Journal of materials science 8 (1997), S. 531-536 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Four different implant materials were installed into the mandibular corner of goats to investigate the trabecular bone response in a mainly unloaded model. The implants were installed using a standardized technique and were left in situ for 12 weeks. One goat had to be sacrificed after surgery because of a broken rib; the other animals healed uneventfully. After sacrifice of the animals, the bone response to the uncoated and the three different Ca–P implants was evaluated histologically and histomorphometrically. Four sections of each implant were evaluated; two were located in the cortical and two in the trabecular bone. Of the 44 retrieved implants, 20 implants appeared to be installed partially in the mandibular canal, as clearly visible on the X-rays. These implants were not used in the histomorphometrical measurements. Histological evaluation showed that the trabecular and cortical bone reactions were similar; there was no significant difference in the percentage of bone contact nor in the amount of bone in contact with the implants. In conclusion this study showed that the mandibular corner is an unsatisfactory model for the installation of implants because of anatomical restrictions. Also, the experiment remained inconclusive about the influence of loading conditions on bone behaviour. Nevertheless, the histological results confirmed the bioactive properties of Ca–P coatings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018542630017
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  • 7
    Electronic Resource
    Electronic Resource
    Influence of rapid heating with infrared radiation on RF magnetron-sputtered calcium phosphate coatings (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 37 (1997), S. 60-67 
    Details
    ISSN: 0021-9304
    Keywords: heat treatment ; calcium phosphate ; coating ; sputter ; implant ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: This study evaluated the effect of rapid heating with infrared radiation on the physico-chemical and morphological properties of radio frequent (RF) magnetron-sputtered calcium phosphate (Ca-P) coatings. About 2.5 μm thick Ca-P coatings were deposited on titanium disks and cylinders. These specimens were left untreated or were heat treated by infrared radiation at 300, 400, 500, 600, and 700°C for 4, 7, 11, 17, and 24 s. Subsequently, the specimens were immersed in simulated body fluid (SBF) for 1 day, 1 week, and 5 weeks. X-ray diffraction measurements showed that heating at 500°C or higher resulted in an increase of coating crystallinity. In addition, FT-IR measurements revealed the appearance of OH peaks in the spectra of samples treated at 500-700°C. Electron probe microanalysis showed that after 5 weeks of immersion about 40-50% of the coatings heat treated at 500 and 600°C was maintained. The coatings heat treated at 700°C showed no dissolution at all. On the other hand, as-coated and 300°C treated films were dissolved within 1 day. Scanning electron microscopy of the samples showed that directly after heat treatment no apparent cracks were present in the coatings. On the basis of these findings, we conclude that rapid heating with infrared radiation around 600°C is the best heat treatment for RF magnetron-sputtered coatings. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 60-67, 1997.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Mechanical and histologic evaluation of Ca-P plasma-spray and magnetron sputter-coated implants in trabecular bone of the goat (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 36 (1997), S. 75-83 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The aim of this study was to investigate the bone response to calcium phosphate (Ca-P) plasma-spray and radiofrequency magnetron sputter-coated implants with comparable roughness. Therefore, tapered conical screw designed implants were installed in the trabecular bone of the femurs of nine goats. They were provided with two types of coatings, a plasma-spray dual coating of fluorapatite and hydroxyapatite (FA/HA-PS) and a titanium plasma-spray coating, covered with an amorphous Ca-P magnetron sputtercoating (TPS/Ca-P-a). These implants were evaluated histologically and mechanically after 3 months of implantation. A well-controlled method to apply and measure a torsional force to load the screw-type implants to the point of failure was introduced. All implants healed uneventful and were well fixed. No significant difference (Student t test, p 〉 0.05) for the torsional failure force was measured for both type of coatings. Nevertheless, SEM revealed differently situated fracture planes. Light microscopy showed intimate bone-implant contact for both types of coatings; original drill margins were still visible. A lamellar type of bone with some remodeling lacunae was shown. Histomorphometry revealed a higher percentage of bone contact for the FA/HA-PS-coated implants (student t test, p 〈 0.05). Measurement of the amount of bone revealed more bone mass around TPS/Ca-P-a-coated implants (analysis of variance and Tukey multiple comparison, p 〈 0.05). © 1997 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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