{"id":{"repo_id":"freiburg-diss","oai_identifier":"oai:freidok.uni-freiburg.de:1630"},"canonical_url":"https://search.dev.ndltd.org/etd/freiburg-diss/oai:freidok.uni-freiburg.de:1630","repository":{"repo_id":"freiburg-diss","name":"University of Freiburg","base_url":"https://freidok.uni-freiburg.de/oai/oai2.php"},"display":{"title":"Age-related proliferative behavior of mandibular osteoblasts : an in vitro study","abstract":"Knowledge of age-related changes occurring in the proliferative behavior of osteoblasts is a necessity for orthodontists because the performance of an orthodontic tooth movement requires a sufficient remodeling ability of the affected bony tissue. This could be affected by several local and systemic factors which influence the proliferative activity of the osteoblast with increasing age. As the activity of osteoblasts obtained from sheep are similar to that of human cells, sheep osteoblast cells were obtained to investigate the limit of the dividing function which could be reached by a senescent osteoblast. In an in vitro study, the proliferation rate of 15 sheep from 3 different age-groups was measured using two different proliferation tests (MTT and EZ4U). These depend on the mitochondrial functional activity of the cells and not only on their staining. The difference in cell number and size between the three age-groups was also determined and statistically analyzed using the Friedman-test. The findings of this study indicated a large variance in the proliferative activity between young, middle-aged, and old specimens with a significant standard deviation in each group. However the middle-aged group always showed the relatively highest mean values, which could be reverted to the maturing phase of the cells when the animal had reached the age of puberty. This developmental stage is normally associated with secretion of many hormones and growth factors. The EZ4U-test proved that some of the individual old cells have shown more proliferation potential than others from the young cells, and secondly by MTT-test the proliferation rate on average was higher in the old than in the young group. This means that ageing may have an influence on the proliferative function of the osteoblasts. Further studies on larger samples are needed, in order to verify the frequency of a high proliferative potential in aged osteoblasts.","abstract_html":"Knowledge of age-related changes occurring in the proliferative behavior of osteoblasts is a necessity for orthodontists because the performance of an orthodontic tooth movement requires a sufficient remodeling ability of the affected bony tissue. This could be affected by several local and systemic factors which influence the proliferative activity of the osteoblast with increasing age. As the activity of osteoblasts obtained from sheep are similar to that of human cells, sheep osteoblast cells were obtained to investigate the limit of the dividing function which could be reached by a senescent osteoblast. In an in vitro study, the proliferation rate of 15 sheep from 3 different age-groups was measured using two different proliferation tests (MTT and EZ4U). These depend on the mitochondrial functional activity of the cells and not only on their staining. The difference in cell number and size between the three age-groups was also determined and statistically analyzed using the Friedman-test. The findings of this study indicated a large variance in the proliferative activity between young, middle-aged, and old specimens with a significant standard deviation in each group. However the middle-aged group always showed the relatively highest mean values, which could be reverted to the maturing phase of the cells when the animal had reached the age of puberty. This developmental stage is normally associated with secretion of many hormones and growth factors. The EZ4U-test proved that some of the individual old cells have shown more proliferation potential than others from the young cells, and secondly by MTT-test the proliferation rate on average was higher in the old than in the young group. This means that ageing may have an influence on the proliferative function of the osteoblasts. Further studies on larger samples are needed, in order to verify the frequency of a high proliferative potential in aged osteoblasts.","abstract_has_math":false,"creators":["Juma'a, Mohammad Samer"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Jonas, Irmtrud"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":null,"date_issued":"","date_published":null,"updated_at":"2026-07-24T02:22:22Z","subjects":["Proliferation","Osteoblasten","Zellkultur","ageing","MTT","EZ4U","osteoblasts"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://freidok.uni-freiburg.de/data/1630","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Jonas, Irmtrud"]},{"key":"dc:creator","label":"Author","values":["Juma'a, Mohammad Samer"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["DoctoralThesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Proliferation","Osteoblasten","Zellkultur","ageing","MTT","EZ4U","osteoblasts"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Knowledge of age-related changes occurring in the proliferative behavior of osteoblasts is a necessity for orthodontists because the performance of an orthodontic tooth movement requires a sufficient remodeling ability of the affected bony tissue. This could be affected by several local and systemic factors which influence the proliferative activity of the osteoblast with increasing age. As the activity of osteoblasts obtained from sheep are similar to that of human cells, sheep osteoblast cells were obtained to investigate the limit of the dividing function which could be reached by a senescent osteoblast. In an in vitro study, the proliferation rate of 15 sheep from 3 different age-groups was measured using two different proliferation tests (MTT and EZ4U). These depend on the mitochondrial functional activity of the cells and not only on their staining. The difference in cell number and size between the three age-groups was also determined and statistically analyzed using the Friedman-test. The findings of this study indicated a large variance in the proliferative activity between young, middle-aged, and old specimens with a significant standard deviation in each group. However the middle-aged group always showed the relatively highest mean values, which could be reverted to the maturing phase of the cells when the animal had reached the age of puberty. This developmental stage is normally associated with secretion of many hormones and growth factors. The EZ4U-test proved that some of the individual old cells have shown more proliferation potential than others from the young cells, and secondly by MTT-test the proliferation rate on average was higher in the old than in the young group. This means that ageing may have an influence on the proliferative function of the osteoblasts. Further studies on larger samples are needed, in order to verify the frequency of a high proliferative potential in aged osteoblasts.","Das Verständnis von altersabhängigen Änderungen im proliferativen Verhalten der Osteoblasten besitzt für den Kieferorthopäden eine große Bedeutung, da die Dürchführung einer orthodontischen Zahnbewegung eine ausreichende Remodellierungsfähigkeit des Knochengewebes erfordert. Dies kann durch lokale und systemische Faktoren beeinflusst werden, die wiederum Einfluss auf die proliferative Aktivität einer Osteoblastenzelle bei zunehmendem Alter nehmen. Abhängig von der Tatsache, dass die biologische Aktivität der der aus Schafen gewonnenen Osteoblasten der menschlicher Zellen ähnlich ist, wurden die in dieser Studie gewonnenen Osteoblasten auf die Limitierung der Teilungsfunktion der alternden Osteoblasten hin untersucht. In einer In-vitro-Studie wurde die Proliferationsrate von Unterkieferosteoblasten von 15 Schafen aus 3 unterschiedlichen Altersgruppen mit zwei unterschiedlichen Proliferationstest-verfahren gemessen (MTT und EZ4U). Beide Tests lassen zusätzlich zur Anfärbung eine Untersuchung der mitochondrischen Funktion der Zellen zu. Der Unterschied in der Zellanzahl und -größe zwischen den drei Altersgruppen wurde statistisch mit dem Friedman-Test evaluiert. Die Resultate dieser Arbeit haben eine große Varianz der proliferativen Aktivität zwischen dem jungen, mittelalten und älteren Tierkollektiv belegt, jeweils mit einer signifikanten Standardabweichung. Bei der Gruppe mittleren Alters wurden die höchsten Mittelwerte gefunden, was auf die Reifungsphase der Zellen zurückzuführen zu sein scheint, wenn das Tier das Pubertätsalter erreicht hat. Dieser Entwicklungsstand steht in Zusammenhang mit der Absonderung verschiedener Hormone und Wachstumsfaktoren. Das mittels EZ4U-Test nachgewiesene stärkere Proliferationspotential bei einigen Zellen des älteren Kollektivs im Vergleich zu einigen Zellen des jungen Kollektivs, und die zweitens beim MTT-Test vorliegende im Durchschnitt höhere Proliferationsrate des älteren Kollektivs verglichen mit dem jungen Kollektiv lässt den Schluss zu, das fortschreitende Zellalterung möglicherweise einen Einfluss auf die proliferative Funktion der Osteoblasten hat. Eine höhere Probenanzahl ist erforderlich, um das Vorhandensein eines hohen Proliferationspotentials bei älteren Osteoblasten weiter zu verifizieren."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Age-related proliferative behavior of mandibular osteoblasts : an in vitro study","Altersabhängiges Proliferationsverhalten von Osteoblasten des Unterkiefers : eine in vitro Studie"]}]}],"canonical_facts":{"dc:contributor":["Jonas, Irmtrud"],"dc:creator":["Juma'a, Mohammad Samer"],"dc:description.abstract":["Knowledge of age-related changes occurring in the proliferative behavior of osteoblasts is a necessity for orthodontists because the performance of an orthodontic tooth movement requires a sufficient remodeling ability of the affected bony tissue. This could be affected by several local and systemic factors which influence the proliferative activity of the osteoblast with increasing age. As the activity of osteoblasts obtained from sheep are similar to that of human cells, sheep osteoblast cells were obtained to investigate the limit of the dividing function which could be reached by a senescent osteoblast. In an in vitro study, the proliferation rate of 15 sheep from 3 different age-groups was measured using two different proliferation tests (MTT and EZ4U). These depend on the mitochondrial functional activity of the cells and not only on their staining. The difference in cell number and size between the three age-groups was also determined and statistically analyzed using the Friedman-test. The findings of this study indicated a large variance in the proliferative activity between young, middle-aged, and old specimens with a significant standard deviation in each group. However the middle-aged group always showed the relatively highest mean values, which could be reverted to the maturing phase of the cells when the animal had reached the age of puberty. This developmental stage is normally associated with secretion of many hormones and growth factors. The EZ4U-test proved that some of the individual old cells have shown more proliferation potential than others from the young cells, and secondly by MTT-test the proliferation rate on average was higher in the old than in the young group. This means that ageing may have an influence on the proliferative function of the osteoblasts. Further studies on larger samples are needed, in order to verify the frequency of a high proliferative potential in aged osteoblasts.","Das Verständnis von altersabhängigen Änderungen im proliferativen Verhalten der Osteoblasten besitzt für den Kieferorthopäden eine große Bedeutung, da die Dürchführung einer orthodontischen Zahnbewegung eine ausreichende Remodellierungsfähigkeit des Knochengewebes erfordert. Dies kann durch lokale und systemische Faktoren beeinflusst werden, die wiederum Einfluss auf die proliferative Aktivität einer Osteoblastenzelle bei zunehmendem Alter nehmen. Abhängig von der Tatsache, dass die biologische Aktivität der der aus Schafen gewonnenen Osteoblasten der menschlicher Zellen ähnlich ist, wurden die in dieser Studie gewonnenen Osteoblasten auf die Limitierung der Teilungsfunktion der alternden Osteoblasten hin untersucht. In einer In-vitro-Studie wurde die Proliferationsrate von Unterkieferosteoblasten von 15 Schafen aus 3 unterschiedlichen Altersgruppen mit zwei unterschiedlichen Proliferationstest-verfahren gemessen (MTT und EZ4U). Beide Tests lassen zusätzlich zur Anfärbung eine Untersuchung der mitochondrischen Funktion der Zellen zu. Der Unterschied in der Zellanzahl und -größe zwischen den drei Altersgruppen wurde statistisch mit dem Friedman-Test evaluiert. Die Resultate dieser Arbeit haben eine große Varianz der proliferativen Aktivität zwischen dem jungen, mittelalten und älteren Tierkollektiv belegt, jeweils mit einer signifikanten Standardabweichung. Bei der Gruppe mittleren Alters wurden die höchsten Mittelwerte gefunden, was auf die Reifungsphase der Zellen zurückzuführen zu sein scheint, wenn das Tier das Pubertätsalter erreicht hat. Dieser Entwicklungsstand steht in Zusammenhang mit der Absonderung verschiedener Hormone und Wachstumsfaktoren. Das mittels EZ4U-Test nachgewiesene stärkere Proliferationspotential bei einigen Zellen des älteren Kollektivs im Vergleich zu einigen Zellen des jungen Kollektivs, und die zweitens beim MTT-Test vorliegende im Durchschnitt höhere Proliferationsrate des älteren Kollektivs verglichen mit dem jungen Kollektiv lässt den Schluss zu, das fortschreitende Zellalterung möglicherweise einen Einfluss auf die proliferative Funktion der Osteoblasten hat. Eine höhere Probenanzahl ist erforderlich, um das Vorhandensein eines hohen Proliferationspotentials bei älteren Osteoblasten weiter zu verifizieren."],"dc:format.medium":["application/pdf"],"dc:subject":["Proliferation","Osteoblasten","Zellkultur","ageing","MTT","EZ4U","osteoblasts"],"dc:title":["Age-related proliferative behavior of mandibular osteoblasts : an in vitro study","Altersabhängiges Proliferationsverhalten von Osteoblasten des Unterkiefers : eine in vitro Studie"],"dc:type":["DoctoralThesis"]},"updated_at":"2026-07-24T02:22:22Z"}