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  • 2000-2004
  • 1985-1989  (4)
  • 1970-1974  (1)
  • 1915-1919
  • 1910-1914
  • Growth  (3)
  • Histoautoradiography  (2)
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  • 2000-2004
  • 1985-1989  (4)
  • 1970-1974  (1)
  • 1915-1919
  • 1910-1914
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  • 1
    Electronic Resource
    Electronic Resource
    A scanning electron microscopic study of the growth of hydroxyapatite crystals (1972)
    Springer
    Calcified tissue international 10 (1972), S. 91-102 
    Details
    ISSN: 1432-0827
    Keywords: Hydroxyapatite ; Calcification ; Phases ; Growth ; Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La croissance cristalline de l'hydroxyleapatite à 25° et à pH constant de 7.4 a été étudiée à l'aide du microscope électronique à balayage. La technique reproductible de croissance par ensemencement à partir de solutions stables sursaturées est utilisée efficacement pour produire des échantillons de minéral à divers stades distincts de croissance. Des changements de phase sont observés avec le progrès de la croissance; ils correspondent dans le temps avec les résultats cinétiques obtenus antérieurement. Un essai de rationalisation est tenté à la lumière des mécanismes proposés pour la formation d'hydroxyleapatite dans des conditionsin vivo.
    Abstract: Zusammenfassung Das Kristallwachstum von Hydroxyapatit bei 25° und einem konstanten pH von 7,4 wurde mit Hilfe eines Raster-Elektronenmikroskopes studiert. Die reproduzierbare Technik des Keimwachstums aus stabilen übersättigten Lösungen wurde mit Erfolg verwendet, um Mineralproben in verschiedenen bestimmten Stadien des Wachstums zu erhalten. Phasenveränderungen wurden beim fortschreitenden Wachstum beobachtet, und diese stimmten zeitlich gut überein mit kinetischen Resultaten, über welche früher berichtet wurde. Es wurde versucht, diese Beobachtungen zu erklären in Anbetracht von Mechanismen, welche für die Bildung von Hydroxyapatit unterin vivo-Bedingungen vorgeschlagen wurden.
    Notes: Abstract The crystal growth of hydroxyapatite at 25° and at a constant pH of 7.4 has been studied with the aid of a scanning electron microscope. The reproducible technique of seeded growth from stable supersaturated solutions was used effectively to produce samples of the mineral at various distinct stages of growth. Phase changes were observed as the growth proceeded and these corresponded favorably in time with kinetic results reported earlier. An attempt was made to rationalize the observations in light of mechanisms proposed for the formation of hydroxyapatite under conditions foundin vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02012539
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Performance of two Picea abies (L.) Karst. stands at different stages of decline (1988)
    Springer
    Oecologia 75 (1988), S. 25-37 
    Details
    ISSN: 1432-1939
    Keywords: Forest decline ; Carbohydrates ; Picea abies ; Growth ; Leaf area index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This is the first in a series of papers on the growth, photosynthetic rate, water and nutrient relations, root distribution and mycorrhizal frequency of two Norway spruce forests at different stages of decline. One of the stands was composed of green trees only while the other included trees ranging in appearance from full green crowns to thin crowns with yellow needles. In this paper we compare the growth and carbohydrate relations of the two stands and examine relationships among growth variables in ten plots. The declining stand produced 65 percent of the wood per ground area compared with the stand in which all trees were green because its foliage produced less wood at any level of leaf area index. The difference in foliage efficiency between the sites could not be explained by differeneces in climate, competition or stand structure. The declining stand appeared to have lower carbon gain as indicated by a smaller increase in reserve carbohydrates before bud break, and weaker sinks for carbohydrates as indicated by less use of the stored carbohydrates than the healthy stand. Thus, growth reduction was probably related to factors which affect both photosynthesis and, even more, the sinks for carbohydrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378810
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  • 3
    Electronic Resource
    Electronic Resource
    Performance of two Picea abies (L.) Karst. stands at different stages of decline (1988)
    Springer
    Oecologia 77 (1988), S. 163-173 
    Details
    ISSN: 1432-1939
    Keywords: Forest decline ; Spruce (Picea abies) ; Nutrients ; Growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A declining, closed-canopy Picea abies (L.) Karst. stand produced as much crown biomass as a healthy stand, although some trees were chlorotic due to magnesium deficiency. The production of wood per unit of leaf area in both stands was related to the foliar magnesium concentration. Although leaf area index and climate were similar at both sites, stemwood production was 35% lower in the declining than in the healthy stand. Nutritional disharmony, rather than a deficiency in a single element, was identified as the mechanism for reduced tree vigor. The role of nutrient stress in forest decline was detected by partitioning the season into three periods reflecting different phenological stages: a canopy growth period in spring, a stem growth period in summer, and a recharge period during the non-growing season. Needle growth was associated with nitrogen supply. Most of the magnesium supply required to meet the demand for foliage growth was retranslocated from mature needles. Magnesium retranslocation was related to concentration of nitrogen and magnesium in those needles before bud break. Retranslocation from mature needles during the phase of canopy production resulted in chlorosis in initially green needles if the magnesium concentration before bud break was low. Nitrogen concentration in 0-year-old needles generally remained constant with increasing supply, indicating that foliage growth was restricted by the supply of nitrogen. In contrast, magnesium concentration generally increased with supply, indicating that magnesium supply for needle growth was sufficient. Much of the magnesium required for wood production was taken up from the soil because stored magnesium was largely used for canopy growth. Uptake at the declining site was probably limited because of restricted root expansion and lower soil magnesium compared to the healthy site. For this reason only wood growth was reduced at the declining site. Because the recharge of magnesium during the non-growing period is dependent on uptake from the soil, it was more limited at the declining that at the healthy stand. However, as nitrogen uptake from the atmosphere may account for an appreciable proportion of the total uptake, and as its supply in the soil at both sites was similar, an unbalanced recharge of nitrogen and magnesium may have occurred at the declining site. If mature needles are unable to recharge with magnesium in proportion to the uptake of nitrogen, chlorosis is likely to occur during the next canopy growth period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379182
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Histoautoradiographische Untersuchungen im Billroth-I-operierten Rattenmagen in Abhängigkeit vom postoperativen Intervall (1985)
    Springer
    Langenbeck's archives of surgery 365 (1985), S. 179-191 
    Details
    ISSN: 1435-2451
    Keywords: Resected stomach ; Carcinogenesis ; Proliferation kinetics ; Histoautoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der operierte Magen gilt heute als Präcancerose im weiteren Sinne. Systematische, histoautoradiographische Untersuchungen zur Proliferationskinetik im operierten Magen im Bereich anastomosierter Schleimhautabschnitte lagen bis heute nicht vor. Mittels histoautoradiographischer Untersuchungen sollte deshalb folgenden Fragen nachgegangen werden: 1. Wie ändert sich die Proliferationskinetik der Magenschleimhaut im Bereich der Anastomose und mit zunehmendem postoperativen Intervall? 2. Ergeben sich Veränderungen der Proliferationskinetik in der anastomosenfernen Corpusschleimhaut? Zur Beantwortung dieser Fragen wurden von 231 nach Billroth I operierten Wistar-Ratten 75 für die histoautoradiographische Analyse ausgewählt. Die Versuchstiere wurden zu festgesetzten Zeitpunkten über ein postoperatives Intervall von 104 Versuchswochen getötet und die Magendarmpräparate für die histoautoradiographische Analyse aufgearbeitet und ausgewertet. Die3H-Markierungsindices im Bereich der magenseitigen Anastomose zeigten während des postoperativen Zeitabschnittes einen charakteristischen Verlauf: Über einen stetigen Anstieg der3H-Markierungsindices bis auf das Vierfache der Norm kam es zwei Jahre nach der Operation wieder zu einem leichten Abfall der Proliferationsaktivität, der aber immer noch mehr als doppelt so hoch wie der Normalwert war. Außerdem wurden ausgedehnte Verschiebungen und Auflösungen der Proliferationszone im Bereich der m-aCorpusschleimhaut hingegen war die Proliferationsaktivität unverändert. Eine über einen langen Zeitpunkt erheblich gesteigerte Zellproliferation im Bereich der magenseitigen Anastomosenschleimhaut, wie sie in unserem Versuchsmodell nachgewiesen werden konnte, ist als Promotionsfaktor der Carcinomentstehung aufzufassen, wie die im Gesamtversuch entstandenen Anastomosencarcinome belegen.
    Notes: Summary Nowadays the resected stomach is considered to be in a precancerous state in the broader sense. Until now there have been no systematic, histoautoradiographic investigations concerning the proliferative kinetics of the resected stomach in the region of anastomosed mucosa sections. Histoautoradiographic investigations should give an answer to the following questions: 1. In which way do the proliferative kinetics of gastric mucosa in the part of the anastomosis change with increasing postoperative interval? 2. Is there a result of variations in the proliferative kinetics of the anastomotic distant mucosa of the fundus? To find an answer to these questions, 75 Wistar-rats out of 231 operated rats (Billroth's 1 st principle) were selected for histoautographic analysis. The laboratory animals were killed at fixed points of time in a postoperative interval of 104 weeks of experiment and the gastrointestinal preparations were worked up and_ interpreted for the histoautographic analysis. During the postoperative period the3H-labelling-indices showed a characteristic course in the part of the gastric anastomosis. After a continuous increase of the 3H-labelling indices up to the fourfold of standard values two years after the operation there was a slight decrease of the proliferative activity. But it still remained twice the normal value. In addition, extended displacements and decompositions of gastric anastomosis mucosa could be observed. However, the proliferative activity in the anastomotid distant mucosa remained unchanged. A cell proliferation of gastric anastomosis increasing considerably and demonstrated in our experiment has to be considered as promotion factor of cancer development. Anastomotic carcinomas developing during the total experiment give evidence for this.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01261145
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  • 5
    Electronic Resource
    Electronic Resource
    Histoautoradiographische Untersuchungen im Billroth-I-operierten Rattenmagen in Abhängigkeit vom postoperativen Intervall (1985)
    Springer
    Langenbeck's archives of surgery 365 (1985), S. 193-203 
    Details
    ISSN: 1435-2451
    Keywords: Resected stomach ; Histoautoradiography ; Carcinogenesis ; Histological changes (alterations)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei 75 nach Billroth I operierten Wistar-Ratten war über ein postoperatives Intervall von 104 Versuchswochen eine bis auf das 4fache erhöhte Zellumsatzrate, verbunden mit ausgedehnten Verschiebungen und Auflösungen der Proliferationszone im Bereich der magenseitigen Anastomose, nachgewiesen worden. Im Verlauf der 104 Versuchswochen entstanden ausnahmslos im Bereich anastomosierter Schleimhautabschnitte adematöscytische Drüsenproliferate, Anastomosenpolypen, dysplastische Drüsenareale und Anastomosencarcinome. In diesen pathologisch-anatomisch abgrenzbaren Veränderungen wurde mittels histoautoradiographischer Methoden die Zellumsatzrate bestimmt, und zwar immer in den Bereichen, in denen die Markierungen am stärksten waren. Die Beurteilung erfolgte in Abhängigkeit vom postoperativen Intervall. Typischerweise lagen bei allen pathologischanatomischen Veränderungen die Herde höchster Markierung in der Peripherie. Als schwerste Komplikation im Bereich anastomosierter Schleimhautabschnitte entstanden in diesem Tiermaterial Carcinome. In diesen Carcinomen fanden sich die Bereiche in höchster mitotischer Aktivität immer in den peripheren Tumorabschnitten, der sogenannten „Invasionsfront”. Die Analyse der autoradiographischen Untersuchungen im Bereich der beschriebenen pathologisch-anatomischen Veränderungen zeigte, daß die veränderte Proliferationskinetik im Sinne einer erheblich gesteigerten Zellumsatzrate auf die besondere Rolle der Anastomosenregion bei der Carcinomentstehung im operierten Magen hinweist.
    Notes: Summary In a postoperative interval of 104 weeks' experience with 75 Wistar rats resected according to Billroth's 1 st principle, the fourfold of standard of proliferative activity in addition to extended displacements and decompositions could be demonstrated. During 104 weeks of experience 8 animals developed in the anastomosed mucosa section adenomatous cystic glandular proliferations, 5 animals anastomotic polypi, 16 animals dysplastic gland areas and 10 animals showed anastomotic carcinomas. For these pathologic-anatomically outlined changes cellular proliferation was analysed by histoautoradiographic methods in parts of highest mitotic activity. The results were interpreted in dependance on their postoperative interval. In all pathologicanatomical changes sources of strongest labelling could be found in the periphery. As most serious complication rats in experiment developed carcinoma in the anastomosed parts of mucosa. The peripheral sections of the carcinoma, so-called “front of invasion”, showed regions of highest mitotic activity. Analysis of histoautoradiographic investigation in pathologic-anatomical change revealed modified proliferation kinetics in the sense of highly increased cell proliferation rates, which refer to the important role of the anastomotic region in the resected stomach.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01261146
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    Paper (German National Licenses)
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