Search

Your search keyword '"Hofmann, Tobias"' showing total 568 results
Start Over Author "Hofmann, Tobias"
568 results on '"Hofmann, Tobias"'

201. Evaluation der intensitätsmodulierten Bestrahlungstechnik für die stereotaktische Strahlentherapie im kraniellen Bereich

Author

Blank, Hilbert, Alheit, Horst, Zips, Daniel, Technische Universität Dresden, Hofmann, Tobias, Blank, Hilbert, Alheit, Horst, Zips, Daniel, Technische Universität Dresden, and Hofmann, Tobias

Abstract

Die fraktionierte stereotaktisch geführte Radiotherapie stellt eine Möglichkeit der Behandlung intrakranieller Tumoren dar, bei denen eine chirurgische Resektion nicht oder nicht vollständig möglich ist. Ziel dieser Arbeit war der Vergleich der Dosisverteilung von Bestrahlungsplänen, die mittels fluenzmodulierter (IMRT) und 3D konformaler stereotaktisch geführter Bestrahlungstechnik (conformal beam) für Hypophysenadenome und petroclivale Meningeome erstellt wurden. Auf Basis des CT-Datensatzes eines Alderson-Phantoms erfolgten zunächst die systematische Untersuchung der IMRT Eingabeparameter und die Definition von Dosis-Volumen-Constraints für beide Tumorentitäten. Im Anschluss wurden die gewonnenen Erkenntnisse bei der fluenzmodulierten Bestrahlungsplanung von 10 realen Patienten, 5 je Tumorentität, angewendet. Zusätzlich wurde für jeden dieser Patienten ein 3D konformaler Bestrahlungsplan erstellt. Die Evaluation der Bestrahlungspläne erfolgte durch verschiedene quantitativer Parameter unter Einbeziehung der subjektiven Beurteilung der Dosisverteilung. Bei beiden Tumorentitäten lieferte in je 4 von 5 Fällen die IMRT einen Vorteil gegenüber der conformal beam Bestrahlung, der vor allem auf der besseren Erfassung, Dosishomogenität und höheren Median-Dosis im bestrahlten Zielvolumen (PTV) beruhte. Komplex geformte Zielvolumina profitierten dabei besonders von der Fluenzmodulation. Dem stand jedoch in einigen Fälle eine stärke Belastung der Risikoorgane (OAR) mit einer höheren Dosis und die generell höhere Anzahl notwendiger Monitoreinheiten gegenüber. Zuletzt wurde auf Basis von MatLAB eine Software entwickelt, welche die Verifikation von stereotaktisch geführten IMRT-Bestrahlungen und die Analyse von Winston-Lutz-Tests ermöglicht.

Published
2007

213. Short-term UVB irradiation significantly increases vitamin D serum concentration in obese patients: a clinical pilot study

Author

Obbarius, Alexander, Berger, Heike, Stengel, Andreas, Garcia, Carmen, Fischer, Felix, Hofmann, Tobias, Rose, Matthias, and Uebelhack, Ralf

Abstract

Deficiency of vitamin D is very common in obese people and treatment by oral supplementation is not effective in all patients. This exploratory pilot study investigated the influence of different doses of short-term ultraviolet B irradiation on serum 25-hydroxyvitamin-D3(25D) and 1,25-dihydroxyvitamin-D3(1,25D) levels in obese compared to normal weight subjects and obese controls. Participants with skin types II and III (Fitzpatrick skin classification) were assigned to six groups including four intervention groups receiving irradiation (three groups of obese and one group of normal weight subjects) and two control groups without treatment (obese and normal weight). Intervention groups received three sessions of whole body UVB irradiation of three different doses (cumulative doses over three sessions: 0.28, 0.70, 1.75 minimal erythema dose) within 1 week of intervention. Serum 25D and 1,25D were measured at baseline and after irradiation. Outcome differences between groups were analyzed using a linear model. Serum 25D levels increased significantly in obese (+23.6 and +26.7%, respectively, p= 0.01) and normal weight (+15.6%, p= 0.02) intervention groups who received medium and high doses of ultraviolet B irradiation compared to control groups (+3.5 and −4.0%, respectively, p= 1.0). The increase in obese patients was 51.4% greater compared to normal weight controls irradiated with equal ultraviolet B doses. Low-level ultraviolet irradiation did not result in a significant change in serum 25D (+7.0%, p= 0.61). We did not detect any significant differences of 1,25D between groups (p= 0.25). The current study indicates that short-term ultraviolet B irradiation increases 25D levels in obese patients.

Published
2017
Full Text
View/download PDF

216. Einfluss der therapeutischen Beziehung auf Lebensqualität und Blutzuckerkontrolle bei Diabetes mellitus

Author

Klapp, B. F., Barckow, D., Joraschky, P., Hofmann, Tobias Thomas Martin, Klapp, B. F., Barckow, D., Joraschky, P., and Hofmann, Tobias Thomas Martin

Abstract

Ziel: Die beiden primären Ziele der Diabetes-Therapie sind eine möglichst optimale Einstellung des Blutzuckers sowie der Erhalt einer vergleichsweise guten Lebensqualität. Für beide Therapieziele konnte eine Vielzahl somatischer und psychischer Determinanten identifiziert werden. Relativ wenig Beachtung fand in diesem Kontext jedoch bislang die Bedeutung der therapeutischen Beziehung. Die vorliegende Dissertation untersucht, inwieweit ein unmittelbarer Zusam-menhang zwischen der Behandlungszufriedenheit der PatientInnen und den beiden anvisierten Therapiezielen besteht. Methodik: 650 PatientInnen (475 Insulin-behandelt, 171 nicht Insulin-behandelt) aus einer universitären Poliklinik, 3 Schwerpunktpraxen und 28 hausärztlichen Einrichtungen wurden befragt. Zur Erfassung der therapeutischen Beziehung wurde die Medical Interview Satisfaction Scale (MISS) verwendet, die Lebensqualität wurde mit dem WHOQOL-BREF gemessen und die Beurteilung der Blutzuckereinstellung erfolgte durch HbA1c-Werte. Die Darstellung der Ergebnisse erfolgte getrennt für mit und ohne Insulin behandelte PatientInnen. Ergebnisse: Für keines der beiden Subkollektive konnte ein Zusammenhang zwischen therapeutischer Beziehung und Blutzuckerkontrolle gefunden werden. Hingegen zeigte sich für beide Therapiegruppen eine signifikante Beziehung zu verschiedenen Aspekten der subjektiv wahrgenommenen Lebensqualität. Schlussfolgerungen: Unterschiede in der Blutzuckereinstellung waren mit der gewählten Methodik sowie dem verwendeten Konstrukt (Behandlungszufriedenheit) in dieser naturalistischen Studie nicht aufzuzeigen und ein Einbeziehen weiterer Dimensionen der therapeutischen Beziehung, insbesondere der ärztlichen Perspektive und der jeweiligen Interaktion, erscheint für weitere Untersuchungen wünschenswert. Auch wenn die signifikanten Ergebnisse in der Interaktion mit Lebensqualität z.T. als gemeinsame Kovarianz zu verschiedenen Persönlichkeitsmerkmalen interpretiert werden können, ergeben sich deutliche Hi, Objective: The primary goals in treating Diabetes are maintaining blood glucose levels as close to normal as possible and making a relatively normal quality of life achievable. A multitude of somatic and psychological determinants for both of these goals could be identified. However, relatively little consideration in this context was given to the importance of the doctor-patient-relationship. This study examines, whether a direct relationship between treatment satisfaction and the primary treatment goals exists. Methods: 650 patients (475 insulin-treated, 171 not insulin-treated) from one universitary outpatient centre, 3 specialized treatment facilities and 28 general practitioners were asked. The doctor-patient-relationship was assessed using the Medical Interview Satisfaction Scale (MISS), health-related quality of life was measured by the WHOQOL-Bref and metabolic control by HbA1c values. Results are presented separately for patients treated with and without insulin. Results: For none of the two subgroups a relationship between doctor-patient-relationship and metabolic control was detected. However, significant interactions were found for both collectives regarding different aspects of quality of life. Conclusions: Differences in metabolic control could not be shown using the chosen methods and the construct treatment satisfaction under routine conditions and further dimensions of the doctor-patient-relationship as the physician's perspective and interactional aspects are likely to be included in future studies. Even while the significant results concerning the interaction with quality of life can be interpreted as a common covariance regarding various personality dispositions there are clear indications that the doctor-patient-relationship is a determinant of health-related quality of life.

Published
2003

217. NUCB2/nesfatin-1 is associated with severity of eating disorder symptoms in female patients with obesity.

Author

Weibert, Elena, Hofmann, Tobias, Elbelt, Ulf, Rose, Matthias, and Stengel, Andreas

Subjects
*EATING disorders in women, *COMPULSIVE eating, *BULIMIA, *WOMEN patients, *EATING disorders, *ANOREXIA nervosa, *OBESITY
Abstract

Nesfatin-1 has been described as an anorexigenic peptide. Comprehensive evidence also points towards an involvement of nesfatin-1 in the modulation of emotional pathways with a sex-specific regulation of nesfatin-1 in association with anxiety. Although the implication of nesfatin-1 in the regulation of food intake is well-established in animals, data in humans are lacking. Therefore, we investigated a possible association of circulating NUCB2/nesfatin-1 with eating disorder symptoms in female and male patients displaying a wide range of body weight. We enrolled 243 inpatients (177 female, 66 male) hospitalized due to anorexia nervosa (n = 66) or obesity (n = 144) or with normal weight and suffering from somatoform, adjustment, depressive or anxiety disorders (n = 33). Plasma samples (NUCB2/nesfatin-1 levels measured by ELISA) and measures of eating disorder symptoms (by EDI-2, range 0–100) were obtained within three days after admission. The study population displayed a distinct prevalence of eating disorder symptoms with female patients with anorexia nervosa (+ 77.0%, p < 0.001) and obesity (+ 87.9%, p < 0.001) reported significantly higher EDI-2 scores than normal weight patients of the same sex. Accordingly, males with anorexia nervosa (+ 39.7%, p < 0.05) and obesity (+ 51.7%, p < 0.001) had significantly higher EDI-2 scores than males with normal weight. Within the same BMI group, women displayed significantly higher scores than men (+ 21.4%, p < 0.05 in patients with anorexia nervosa, + 18.8%, p < 0.001 in participants with obesity). We observed a positive correlation between NUCB2/nesfatin-1 levels and EDI-2 total scores in female patients with obesity (r = 0.285, p = 0.015), whereas no associations were found in othe r subgroups. A positive correlation between NUCB2/nesfatin-1 levels and BMI was only observed in the male study population (r = 0.315, p = 0.018). NUCB2/nesfatin-1 plasma levels were positively associated with EDI-2 total scores in women with obesity, while no association was observable in men. The lacking association of NUCB2/nesfatin-1 and EDI-2 total scores in female patients with anorexia nervosa might be due to already low NUCB2/nesfatin-1 plasma levels. Whether NUCB2/nesfatin-1 is selectively involved in eating behavior in women with obesity will have to be further investigated. • NUCB2/nesfatin-1 might be involved in disordered eating behavior in a sex-specific way. • Peripheral NUCB2/nesfatin-1 is positively associated with disordered eating in women with obesity. • NUCB2/nesfatin-1 levels are positively correlated with BMI in males with obesity. • Women display higher scores in Eating Disorder Inventory-2 than men. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

219. Nesfatin-130−59 Injected Intracerebroventricularly Differentially Affects Food Intake Microstructure in Rats Under Normal Weight and Diet-Induced Obese Conditions.

Author

Prinz, Philip, Teuffel, Pauline, Lembke, Vanessa, Kobelt, Peter, Hofmann, Tobias, Rose, Matthias, Klapp, Burghard F., Stengel, Andreas, and Goebel-Stengel, Miriam

Subjects
APPETITE depressants, STIMULUS satiation, REDUCING diets
Abstract

Nesfatin-1 is well-established to induce an anorexigenic effect. Recently, nesfatin-130−59, was identified as active core of full length nesfatin-11−82 in mice, while its role in rats remains unclear. Therefore, we investigated the effects of nesfatin-130−59 injected intracerebroventricularly (icv) on the food intake microstructure in rats. To assess whether the effect was also mediated peripherally we injected nesfatin-130−59 intraperitoneally (ip). Since obesity affects the signaling of various food intake-regulatory peptides we investigated the effects of nesfatin-130−59 under conditions of diet-induced obesity (DIO). Male Sprague–Dawley rats fed ad libitum with standard diet were icv cannulated and injected with vehicle (5μl ddH2O) or nesfatin-130−59 at 0.37, 1.1, and 3.3μg (0.1, 0.3, 0.9 nmol/rat) and the food intake microstructure assessed using a food intake monitoring system. Next, naïve rats were injected ip with vehicle (300 μl saline) or nesfatin-130−59 (8.1, 24.3, 72.9 nmol/kg). Lastly, rats were fed a high fat diet for 10 weeks and those developing DIO were icv cannulated. Nesfatin-1 (0.9 nmol/rat) or vehicle (5 μl ddH2O) was injected icv and the food intake microstructure assessed. In rats fed standard diet, nesfatin-130−59 caused a dose-dependent reduction of dark phase food intake reaching significance at 0.9 nmol/rat in the period of 4–8 h post injection (−29%) with the strongest reduction during the fifth hour (−75%), an effect detectable for 24 h (−12%, p < 0.05 vs. vehicle). The anorexigenic effect of nesfatin-130−59 was due to a reduction in meal size (−44%, p < 0.05), while meal frequency was not altered compared to vehicle. In contrast to icv injection, nesfatin-130−59 injected ip in up to 30-fold higher doses did not alter food intake. In DIO rats fed high fat diet, nesfatin-130−59 injected icv reduced food intake in the third hour post injection (−71%), an effect due to a reduced meal frequency (−27%, p < 0.05), while meal size was not altered. Taken together, nesfatin-130−59 is the active core of nesfatin-11−82 and acts centrally to reduce food intake in rats. The anorexigenic effect depends on the metabolic condition with increased satiation (reduction in meal size) under normal weight conditions, while in DIO rats satiety (reduction in meal frequency) is induced. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

220. Sex-specific regulation of NUCB2/nesfatin-1: Differential implication in anxiety in obese men and women.

Author

Hofmann, Tobias, Elbelt, Ulf, Ahnis, Anne, Rose, Matthias, Klapp, Burghard F., and Stengel, Andreas

Subjects
*ANXIETY, *OVERWEIGHT persons, *APPETITE depressants, *PEPTIDE hormones, *COMORBIDITY
Abstract

Nesfatin-1 is cleaved from nucleobindin2 (NUCB2) and implicated in the regulation of hunger and satiety as anorexigenic peptide hormone. Circulating NUCB2/nesfatin-1 is elevated in obesity and decreased in anorexia nervosa. In addition, a role in the regulation of stress, anxiety and depression has been demonstrated. First evidence suggested that NUCB2/nesfatin-1 might be regulated in a sex-specific manner. Thus, we investigated NUCB2/nesfatin-1 plasma levels in association with perceived stress, anxiety and depressiveness in obese men and women. We enrolled 140 inpatients (87 female, 53 male; body mass index, BMI, 30.3–81.7 kg/m 2 ) hospitalized due to obesity with mental and somatic comorbidities. Perceived stress (PSQ-20), anxiety (GAD-7), and depressiveness (PHQ-9) were measured psychometrically, and at the same time NUCB2/nesfatin-1 plasma levels by ELISA. Males and females did not differ in terms of age and BMI. NUCB2/nesfatin-1 did not show a correlation with age or BMI. Mean NUCB2/nesfatin-1 levels (+25%, p < 0.001) as well as mean scores for perceived stress (+26%, p < 0.01), anxiety (+54%, p < 0.001) and depressiveness (+32%, p = 0.02) were higher in females compared to males. Scores for perceived stress ( r = 0.39; p < 0.001) and depressiveness ( r = 0.35; p < 0.01) showed a positive correlation with NUCB2/nesfatin-1 in women, while in men no correlation was observed ( p > 0.19). The strongest association was observed between NUCB2/nesfatin-1 and anxiety with a positive correlation in women ( r = 0.54; p < 0.001), while in men even an inverse correlation was found ( r = −0.32; p = 0.03). This result was reflected in higher NUCB2/nesfatin-1 levels in women with high versus low anxiety (+51%, p < 0.001) and an opposite alteration in men (−17%, p = 0.04) after a median split into two groups with high and low anxiety. In conclusion, circulating NUCB2/nesfatin-1 showed a positive correlation with anxiety, perceived stress, and depressiveness in obese women. In men, no correlation with perceived stress and depressiveness was observed, whereas the association with anxiety was inverse, pointing towards a sex-specific regulation. These results corroborate the suggestion of NUCB2/nesfatin-1 being relevantly involved in the regulation of mood and stress in a sex-specific way. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

224. BackMatter.

Author

Hofmann, Tobias

Published
2012

239. The Double Curse of Lacking Capacity. Evidence from an Instrumental Variable Approach to the Making and Taking of European Environmental Policies.

Author

Börzel, Tanja A. and Hofmann, Tobias

Subjects
*INTERNATIONAL economic integration, *SUPRANATIONALISM, *ENVIRONMENTAL policy, *ECONOMETRICS
Abstract

In this paper, we integrate the literature that is concerned with how to conceptualize and explain the effect of member states on processes and outcomes of regional integration with the literature on the responses of member states to the impact of supranational processes and institutions. This is done by analyzing the role of the EU members as shapers and takers of European environmental policies. Thereby, we try to simultaneously answer the two following questions: (i) Why do some member states achieve a better European policy fit than others? (ii) Why do some members infringe (even) on (fitting) environmental policies more frequently than others? We argue that member states that are good shapers are also effective takers of supranational policies â€" not only due to the better fit between obligations and domestic settings, but also because the factors that enable member states to shape environmental policies help them to ensure their effective implementation. In order to develop and test this argument, our paper proceeds in three steps. Drawing on the two-level games literature, the first part presents a theoretical framework that systematically links the making and taking stages of supranational policies. In the second part we employ econometric methods to assess the impact of several factors identified in the relevant literature against empirical evidence from the field of European environmental policy. The paper concludes with a discussion on the generalizability of our findings. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]

Published
2008

240. Bookmap – A Topic Maps Based Web Application for Organising Bookmarks.

Author

Hofmann, Tobias and Pradella, Martin

Abstract

This paper proposes a basic ontology for use in topic maps storing semantic information on bookmark collections. Furthermore, we introduce a data model allowing to implement such a system on a LAMP (Linux, Apache, MySQL, PHP) platform, extended with the Cake-PHP framework. A prototype has been developed as proof of concept, where the use of AJAX and drag and drop capabilities in the browser resulted in a good user experience during a preliminary user evaluation. [ABSTRACT FROM AUTHOR]

Published
2008
Full Text
View/download PDF

241. Recalcitrance, Inefficiency, and Support for European Integration: Why Member States Do (Not) Comply with European Law.

Author

Boerzel, Tanja and Hofmann, Tobias

Subjects
*INTERNATIONAL law, *LEGAL compliance, *POLITICAL corruption, EUROPEAN politics & government
Abstract

This paper seeks to explain inter-state variation in non-compliance with European law. While noncompliance has not significantly increased over time, some member states violate European law more frequently than others. In order to account for the variance observed, we draw on three prominent approaches in the compliance literature - enforcement, management, and legitimacy. In the first place, we develop a set of hypotheses for each of the three theories. We then discuss how they can be combined in theoretically consistent ways and develop three integrated models. Finally, we empirically test these models drawing on a unique and comprehensive dataset, which comprises more than 6,300 instances of member state non-compliance with European law between 1978 and 1999. The empirical findings show that the combined model of the enforcement and the management approach turns out to have the highest explanatory power. Politically powerful member states are most likely to violate European law while the best compliers are small countries with highly efficient bureaucracies. Yet, administrative capacity also matters for powerful member states. The UK and Germany are much more compliant than France and Italy, which command similar political power but whose administrations are ridden by bureaucratic inefficiency and corruption. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]

Published
2007

242. Currency Unions and the Demand for Protection.

Author

Hofmann, Tobias and Schaffer, Lena

Subjects
*INTERNATIONAL trade, *MONETARY unions, *PROTECTIONISM, *ECONOMIC competition
Abstract

In this paper, we analyze the effects of the Euro on trade and protection. To be more precise, we empirically test our theoretically developed argument that the increase of trade between the member states of currency unions should entail a rise in the demand for industry-specific protectionism. What is the rationale for this argument? With the advent of currency unions, import-competing producers find themselves in a more pronounced competition than before. Since the currency risk that used to be involved in buying goods from producers abroad disappears, the competitive position of national producers is weakened. To restore this position and to regain lost rents, national import-competing producers demand protection from the government as the main supplier of protection. In turn, national governments, taking into account their political support functions, then decide upon the increase of protection within given bounds. In short, this seemingly counter-intuitive relation between currency unions and protection we hypothesize is the consequence of a shift from natural barriers to trade - such as exchange rate volatilities and transaction costs - to such artificial barriers as higher regulative standards, subsidies, or simply tariffs. With respect to European Monetary Union, we econometricly analyze whether that the single currency has to some extent only relocated and disguised the bumps instead of truly leveled the playing field for companies and businesses in Europe. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]

Published
2007

Catalog

Books, media, physical & digital resources
See catalog results