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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
421

The Effects of Menstrual Cycle Phases and Adiposity on Energy Balance in Women

McNeil, Jessica N. 27 October 2011 (has links)
Energy intake (EI) and energy expenditure (EE) across the menstrual cycle (MC), while considering body adiposity, have not been previously evaluated in the same individuals. This study mainly examined the variations in energy balance (EB) across MC. Seventeen women (Body fat-DXA:28.5%) participated in three identical sessions during distinct phases of the MC: Early-follicular, Late-follicular/ovulation and Mid-luteal (confirmed by basal temperature and sex-steroid hormones). EI, resting metabolic rate (RMR), physical-activity EE (PAEE), severity of PMS, leptin and relative-reinforcing value (RRV) of preferred foods were measured during each phase. No differences in body fat, EI, RMR, PAEE, leptin and RRV of food were noted across MC. Trends were noted in preferred snack (p=0.06) and combined snack/fruit (p=0.06) intakes, while differences were noted in severity of PMS (p<0.05) across phases. Changes in EB across the MC were not noted. PMS was more severe, and preferred snack and combined snack/fruit intakes were slightly higher during mid-luteal phase.
422

The relationship of obesity-related metabolic hormones and prognosis in young women with breast cancer /

Johnson, Lisa Godefroy. January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 79-87).
423

Dietary calcium intake and obesity in adult women : the POWIRS study / Petro Hannie Rautenbach

Rautenbach, Petro Hannie January 2004 (has links)
Background: The role of dietary calcium in weight management is gaining support in the nutrition research community. It has been hypothesized that high calcium diets protect against fat gain by creating a balance of lipolysis over lipogenesis in adipocytes (Zemel et al., 2000) and that a diet deficient in calcium is associated with higher body weight and that augmenting calcium intake may reduce weight and fat gain or enhance fat loss (Shapses et al., 2004). Objectives: A lack of baseline data on the physical, physiological and mental effects of obesity on urban African women was the motivation for the POWIRS (Profiles of Obese Women with Insulin Resistance Syndrome) study. The aim of the study was to assess the effects of obesity on health determinants of urban African and white women by comparing the lifestyle and risk factors for non-communicable diseases (NCDs) of lean, overweight and obese subjects. This led to a multi-disciplinary cross-sectional case-control study in which health determinants and health status, as well as the underlying mechanistic relationships between these factors were measured in a sample of African women volunteers. The study was repeated a year later, done in a sample of white women volunteers, POWIRS II. The effect of calcium intake on body composition was assessed during this study. Methods: One hundred and two apparently healthy urban African women, between the ages of 20 and 50 years participated in the first phase of this case-control cross-sectional survey. For a period of about three weeks, each afternoon ten subjects were to report at a Metabolic Unit Facility (consisting of 10 single bedrooms, 2 bathrooms, a living room and kitchen). Each subject received a "participant sheet" which guided them through the different research 'stations' where the various measurements were done. During the course of the evening demographic questionnaires were filled in and all anthropometric measurements were taken, except weight and height measurements. All participants received an identical light supper which excluded alcohol and caffeine at 20h00, went to sleep before 23h00 and fasted overnight. From 06h00 in the morning weight, height and blood pressure measurements were taken. After a fasting blood sample was taken, a two-hour glucose tolerance test commenced. Subjects received a breakfast and afterwards habitual dietary intake questionnaires were completed. Results: Mean total dietary calcium intake as significantly higher in white women (POWIRS II), with a mean intake 1053.8 mg per day, as opposed to a mean intake of 494.8 mg calcium per day in the blacks subjects (POWIRS I). Mean fat intake in the black subjects was 59.3 g per day, and in the white women 103.1 g per day. Thus the calcium:fat ratio in white women was higher than in black women (11.0 and 8.4 respectively). After adjustment for age and total dietary energy intake, significant negative correlations were found between dietary calcium intake and various variables, only in the white subjects. These were BMI (r=-0.255, p=0.01), percentage body fat (r=-0.252, p=0.01), fasting insulin (r=-0.205, p=0.05) and fasting glucose (r=-0.199, p=0.046). The calcium:fat ratio correlated negatively with BMI (r=-0.378, p<0.0001), percentage body fat (r=-0.401, p<0.0001), fasting glucose (r=-0.229, p=0.02), fasting insulin (r=-0.212, p=0.04) and plasma leptin (r=-0.284, p=0.004). Adjustment for smoking resulted in slightly different correlation coefficients, but similar significant correlations were still found. The only significant association that was found in the black population, was a negative correlation between dietary calcium intake and systolic blood pressure (p=0.03) as well as diastolic blood pressure (p=0.04). After adjustment for age, smoking and dietary energy intake no significant correlations were found in the black subjects. Conclusion: The results from the POWIRS study in white women are consistent with the hypothesis that there may be an inverse relationship between adiposity and calcium intake. In our study higher calcium intakes were associated with lower body fat, lower BMI, lower fasting glucose and insulin, as well as plasma leptin in white women. The association seems to be significant in subjects with high intakes of fat and calcium (as seen in the white women). / Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2005.
424

Weighted hypergroups and some questions in abstract harmonic analysis

2013 November 1900 (has links)
Weighted group algebras have been studied extensively in Abstract Harmonic Analysis.Complete characterizations have been found for some important properties of weighted group algebras, namely, amenability and Arens regularity. Also studies on some other features of these algebras, say weak amenability and isomorphism to operator algebras, have attracted attention. Hypergroups are generalized versions of locally compact groups. When a discrete group has all its conjugacy classes finite, the set of all conjugacy classes forms a discrete commutative hypergroup. Also the set of equivalence classes of irreducible unitary representations of a compact group forms a discrete commutative hypergroup. Other examples of discrete commutative hypergroups come from families of orthogonal polynomials. The center of the group algebra of a discrete finite conjugacy (FC) group can be identified with a hypergroup algebra. For a specific class of discrete FC groups, the restricted direct products of finite groups (RDPF), we study some properties of the center of the group algebra including amenability, maximal ideal space, and existence of a bounded approximate identity of maximal ideals. One of the generalizations of weighted group algebras which may be considered is weighted hypergroup algebras. Defining weighted hypergroups, analogous to weighted groups, we study a variety of examples, features and applications of weighted hypergroup algebras. We investigate some properties of these algebras including: dual Banach algebra structure, Arens regularity, and isomorphism with operator algebras. We define and study Folner type conditions for hypergroups. We study the relation of the Folner type conditions with other amenability properties of hypergroups. We also demonstrate some results obtained from the Leptin condition for Fourier algebras of certain hypergroups. Highlighting these tools, we specially study the Leptin condition on duals of compact groups for some specific compact groups. An application is given to Segal algebras on compact groups.
425

Dietary calcium intake and obesity in adult women : the POWIRS study / Petro Hannie Rautenbach

Rautenbach, Petro Hannie January 2004 (has links)
Background: The role of dietary calcium in weight management is gaining support in the nutrition research community. It has been hypothesized that high calcium diets protect against fat gain by creating a balance of lipolysis over lipogenesis in adipocytes (Zemel et al., 2000) and that a diet deficient in calcium is associated with higher body weight and that augmenting calcium intake may reduce weight and fat gain or enhance fat loss (Shapses et al., 2004). Objectives: A lack of baseline data on the physical, physiological and mental effects of obesity on urban African women was the motivation for the POWIRS (Profiles of Obese Women with Insulin Resistance Syndrome) study. The aim of the study was to assess the effects of obesity on health determinants of urban African and white women by comparing the lifestyle and risk factors for non-communicable diseases (NCDs) of lean, overweight and obese subjects. This led to a multi-disciplinary cross-sectional case-control study in which health determinants and health status, as well as the underlying mechanistic relationships between these factors were measured in a sample of African women volunteers. The study was repeated a year later, done in a sample of white women volunteers, POWIRS II. The effect of calcium intake on body composition was assessed during this study. Methods: One hundred and two apparently healthy urban African women, between the ages of 20 and 50 years participated in the first phase of this case-control cross-sectional survey. For a period of about three weeks, each afternoon ten subjects were to report at a Metabolic Unit Facility (consisting of 10 single bedrooms, 2 bathrooms, a living room and kitchen). Each subject received a "participant sheet" which guided them through the different research 'stations' where the various measurements were done. During the course of the evening demographic questionnaires were filled in and all anthropometric measurements were taken, except weight and height measurements. All participants received an identical light supper which excluded alcohol and caffeine at 20h00, went to sleep before 23h00 and fasted overnight. From 06h00 in the morning weight, height and blood pressure measurements were taken. After a fasting blood sample was taken, a two-hour glucose tolerance test commenced. Subjects received a breakfast and afterwards habitual dietary intake questionnaires were completed. Results: Mean total dietary calcium intake as significantly higher in white women (POWIRS II), with a mean intake 1053.8 mg per day, as opposed to a mean intake of 494.8 mg calcium per day in the blacks subjects (POWIRS I). Mean fat intake in the black subjects was 59.3 g per day, and in the white women 103.1 g per day. Thus the calcium:fat ratio in white women was higher than in black women (11.0 and 8.4 respectively). After adjustment for age and total dietary energy intake, significant negative correlations were found between dietary calcium intake and various variables, only in the white subjects. These were BMI (r=-0.255, p=0.01), percentage body fat (r=-0.252, p=0.01), fasting insulin (r=-0.205, p=0.05) and fasting glucose (r=-0.199, p=0.046). The calcium:fat ratio correlated negatively with BMI (r=-0.378, p<0.0001), percentage body fat (r=-0.401, p<0.0001), fasting glucose (r=-0.229, p=0.02), fasting insulin (r=-0.212, p=0.04) and plasma leptin (r=-0.284, p=0.004). Adjustment for smoking resulted in slightly different correlation coefficients, but similar significant correlations were still found. The only significant association that was found in the black population, was a negative correlation between dietary calcium intake and systolic blood pressure (p=0.03) as well as diastolic blood pressure (p=0.04). After adjustment for age, smoking and dietary energy intake no significant correlations were found in the black subjects. Conclusion: The results from the POWIRS study in white women are consistent with the hypothesis that there may be an inverse relationship between adiposity and calcium intake. In our study higher calcium intakes were associated with lower body fat, lower BMI, lower fasting glucose and insulin, as well as plasma leptin in white women. The association seems to be significant in subjects with high intakes of fat and calcium (as seen in the white women). / Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2005.
426

Die verband tussen leptien, liggaamsamestelling en fisieke fiksheid in swart adolessente : die PLAY-studie / Mariëtte Swanepoel

Swanepoel, Mariëtte January 2006 (has links)
Leptin is a protein hormone primarily secreted by the subcutaneous adipose tissue and is responsible for regulating the energy balance. Individuals with more adipose tissue have much higher leptin levels and often suffer from a condition known as leptin resistance. Various factors such as gender, age, ethnicity, diet and physical activity influence the body's leptin concentration. Males have lower leptin levels than females of the same age and body fat content. Black people tend to have higher leptin concentrations than white people because of a more subcutaneous adipose tissue distribution. Physical activity serve as a main manipulator of the body's energy balance and influence leptin concentration through various adaptations associated with a more favorable body composition such as, an increase in lean tissue and a decrease in body fat. The object of this study was firstly to investigate the association between body composition - with special emphasis on adipose tissue and leptin concentration in black adolescent boys and girls of the North-West Province of South Africa. Secondly, the study aimed to determine the influence of physical fitness components and leptin concentration in the same population. In this study, 148 girls and 114 boys supplied overnight fasting blood samples. Anthropometric data: length (m), weight (kg), skin folds (mm) and circumferences of the waist (cm) and hip (cm) were measured. The percentage body fat were also measured in the BOD-POD. Finally a battery of physical fitness tests were done which included: the maximum number of sit-ups, push-ups and the bleep-test for indirect V&-max. Spearman Rank Order correlations determined that there should be adjusted for age and Tanner stage. Partial correlations were done with body composition variables, [BMI (body mass index), SSF (sum of 6 skin folds), body fat percentage], and physical fitness variables, bush-ups, sit-ups and indirect V02-max]. In both genders a strong positive relationship occurred between all the above mentioned body composition variables and leptin. In boys the strongest correlation (I= 0.8420) was found between SSF and leptin levels. In girls the strongest correlation (r = 0.7489) was found between BMI and leptin concentration. In both genders, body fat percentage indicated the lowest correlation, although it was still significant. In both genders the indirect V02-max values indicated a significant negative relationship with serum leptin concentration, although it was weak, it was the highest in boys (r = - 0314). In girls the indirect V02-max values (r = -0.235) and the maximum amount of push-ups (r = -0205) indicated significant, but weak correlations. According to the results of this study it is clear that serum leptin concentration has a strong positive relationship with body fat, more accurate, with the subcutaneous adipose tissue. It was also indicated that baseline physical fitness in these black adolescents from the selected school in Potchefstroom, North-west Province (South Africa) are statistically significant negatively correlated with leptin levels, although it was not a strong correlation. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2006.
427

The Effects of Menstrual Cycle Phases and Adiposity on Energy Balance in Women

McNeil, Jessica N. 27 October 2011 (has links)
Energy intake (EI) and energy expenditure (EE) across the menstrual cycle (MC), while considering body adiposity, have not been previously evaluated in the same individuals. This study mainly examined the variations in energy balance (EB) across MC. Seventeen women (Body fat-DXA:28.5%) participated in three identical sessions during distinct phases of the MC: Early-follicular, Late-follicular/ovulation and Mid-luteal (confirmed by basal temperature and sex-steroid hormones). EI, resting metabolic rate (RMR), physical-activity EE (PAEE), severity of PMS, leptin and relative-reinforcing value (RRV) of preferred foods were measured during each phase. No differences in body fat, EI, RMR, PAEE, leptin and RRV of food were noted across MC. Trends were noted in preferred snack (p=0.06) and combined snack/fruit (p=0.06) intakes, while differences were noted in severity of PMS (p<0.05) across phases. Changes in EB across the MC were not noted. PMS was more severe, and preferred snack and combined snack/fruit intakes were slightly higher during mid-luteal phase.
428

Μελέτη της έκφρασης λιποκινών και του υποδοχέα CB1 των ενδοκανναβινοειδών σε περιαορτικό και επικαρδιακό λιπώδη ιστό ανθρώπου και συσχέτιση με την αθηροσκλήρωση

Σπύρογλου, Σοφία 27 December 2010 (has links)
Οι λιποκίνες αποτελούν πρωτεϊνικά προϊόντα του λιπώδους ιστού με αυτοκρινείς, παρακρινείς και ενδοκρινείς δράσεις που εμπλέκονται στην παθογένεια της καρδιαγγειακής νόσου. Η τοπική παραγωγή λιποκινών, ειδικά από τον περιαγγειακό λιπώδη ιστό, μπορεί να επηρεάσει τη φυσιολογία και την παθολογία των αγγείων. Το ενδοκανναβινοειδές σύστημα σχετίζεται με τη ρύθμιση της ενδοκρινούς λειτουργίας του λιπώδους ιστού, αλλά και με την παθογένεια της αθηροσκλήρωσης. Μελετήσαμε την έκφραση της αντιπονεκτίνης, της βισφατίνης, της λεπτίνης και των νεότερων λιποκινών χεμερίνης και βασπίνης, καθώς και του υποδοχέα ενδοκανναβινοειδών CB1 σε ανθρώπινο περιαορτικό και επικαρδιακό λιπώδη ιστό, καθώς και τη συσχέτισή τους με την αορτική και τη στεφανιαία αθηροσκλήρωση. Εφαρμόστηκε ανοσοϊστοχημική χρώση για τις λιποκίνες και τον CB1 σε δείγματα ανθρώπινου περιαορτικού, περιστεφανιαίου και επικαρδιακού λίπους της κορυφής της καρδιάς. Οι αθηροσκληρωτικές βλάβες στο παρακείμενο αγγειακό τοίχωμα αξιολογήθηκαν με βάση την κατάταξη του AHA. Οι λιποκίνες εκφράστηκαν στον περιαγγειακό και επικαρδιακό λιπώδη ιστό της κορυφής και – με εξαίρεση την αντιπονεκτίνη – στα αγγειακά λεία μυικά κύτταρα και στα αφρώδη κύτταρα των αθηροσκληρωτικών βλαβών. Ο CB1 εκφράστηκε στον περιαορτικό και επικαρδιακό λιπώδη ιστό, καθώς και στα αορτικά και στεφανιαία αγγειακά λεία μυικά κύτταρα. Η αορτική αθηροσκλήρωση συσχετίστηκε θετικά με την έκφραση της χεμερίνης, της βασπίνης, της βισφατίνης και της λεπτίνης στο περιαορτικό λίπος. Η στεφανιαία αθηροσκλήρωση συσχετίστηκε θετικά με την έκφραση της χεμερίνης και της βασπίνης στο περιστεφανιαίο λίπος. Η έκφραση της αντιπονεκτίνης στο λιπώδη ιστό συσχετίστηκε αρνητικά τόσο με την αορτική όσο και με τη στεφανιαία αθηροσκλήρωση. Η έκφραση λιποκινών στον επικαρδιακό λιπώδη ιστό της κορυφής δε συσχετίστηκε με την αθηροσκλήρωση. Επίσης, η έκφραση του CB1 δε συσχετίστηκε με την αορτική ή με τη στεφανιαία αθηροσκλήρωση. Συμπερασματικά, παρατηρήθηκε: α) διαφορετικό προφίλ έκφρασης της αντιπονεκτίνης, βισφατίνης, λεπτίνης, χεμερίνης, βασπίνης και του CB1 στον περιαορτικό, περιστεφανιαίο και επικαρδιακό λιπώδη ιστό της κορυφής, β) συσχέτιση των λιποκινών, αλλά όχι του CB1, με την αορτική ή και με τη στεφανιαία αθηροσκλήρωση, με χαρακτηριστικό τρόπο για κάθε λιποκίνη. Η τοπική παραγωγή λιποκινών ενδεχομένως επηρεάζει ποικιλοτρόπως την αθηροσκληρωτική διαδικασία σε διαφορετικές θέσεις. / Adipokines are protein products of adipose tissue with autocrine, paracrine and endocrine actions, which have been implicated in the pathogenesis of cardiovascular disease. Locally produced adipokines, especially by periadventitial adipose tissue, may affect vascular physiology and pathology. The endocannabinoid system has also been implicated in the pathogenesis of atherosclerosis and in adipose tissue endocrine function regulation. We investigated the expression of adiponectin, visfatin, leptin and novel adipokines chemerin and vaspin, as well as CB1 endocannabinoid receptor, in human periaortic and epicardial adipose tissue, as well as their correlation to aortic and coronary atherosclerosis. Standard immunohistochemical staining for the adipokines and CB1 was performed on samples of human periaortic, pericoronary and apical epicardial adipose tissue. Atherosclerotic lesions of the adjacent vascular wall were assessed using the AHA classification. Adipokines were expressed in periadventitial and apical epicardial adipose tissue and - except for adiponectin - in vascular smooth muscle cells and foam cells in atherosclerotic lesions. CB1 was expressed in periaortic and epicardial adipose tissue, as well as in aortic and coronary vascular smooth muscle cells. Aortic atherosclerosis was positively correlated with chemerin, vaspin, visfatin and leptin periaortic fat expression. Coronary atherosclerosis was positively correlated with chemerin and visfatin pericoronary fat expression. Adipose tissue adiponectin expression was negatively correlated to atherosclerosis in both locations. Expression of adipokines in apical epicardial fat was not associated to atherosclerosis. CB1 expression was not correlated with either aortic or coronary atherosclerosis. Our results show: a) a different expression pattern of adiponectin, visfatin, leptin, chemerin, vaspin and CB1 in periaortic, pericoronary and apical epicardial adipose tissue, b) a correlation of these adipokines - but not CB1 - with either aortic or coronary atherosclerosis or both in a pattern characteristic for each adipokine and suggest that locally produced adipokines might differently affect the atherosclerotic process in different locations.
429

Διερεύνηση της σχέσης επιπέδων λεπτίνης και επιπέδων προ- και αντι-φλεγμονωδών κυτταροκινών σε νεογνά με σκοπό την αναζήτηση πιθανής συμβολής αυξημένων επιπέδων λεπτίνης στην παθογένεια αυτοάνοσων νοσημάτων

Ράπτης, Γεώργιος 06 August 2013 (has links)
Η λεπτίνη παράγεται από τα κύτταρα του λιπώδους ιστού, καθώς και από άλλους ιστούς συμπεριλαμβανομένων του πλακούντος και ρυθμίζει τη πρόσληψη τροφής, τη κατανάλωση ενέργειας, την αναπαραγωγική διαδικασία και τις ανοσολογικές λειτουργίες. Για τη διερεύνηση του ρόλου της λεπτίνης επί του νεογνικού ανοσολογικού συστήματος μετρήσαμε τα επίπεδα λεπτίνης και κυτταροκινών (INF-γ, TNF-α, IL-2, IL-4, IL-10 και IL-12) στον ορό αίματος ομφαλίου λώρου 481 φυσιολογικών νεογνών τα οποία γεννήθηκαν από υγιείς μητέρες. 317 ήταν νεογνά με ιδανικό βάρος γέννησης για την ηλικία κύησης (AGA) και 164 έφεραν αυξημένο βάρος για την ηλικία κύησης (LGA). Η ενδιάμεση συγκέντρωση λεπτίνης σε ολόκληρο το δείγμα ήταν 11.6 ng/ml. Στο 12% AGA νεογνών, τα επίπεδα λεπτίνης ήταν υψηλότερα του μέσου όρου (ενδιάμεση τιμή 34 ng/ml). Στο 33% των νεογνών αυτών (4% του ολικού δείγματος) τα επίπεδα λεπτίνης κυμαίνονταν μεταξύ 37.5-204 ng/ml, στην ομάδα αυτή βρέθηκαν επίσης υψηλά επίπεδα ιντερφερόνης-γ (μέση τιμή 27.11 pg/ml, διακύμανση 17.5-38.5 pg/ml). Κατόπιν μελετήσαμε εάν η λεπτίνη μπορεί να επηρεάσει τη γονιδιακή έκφραση κυτταροκινών στα Τ κύτταρα και μονοκύτταρα αίματος ομφαλίου λώρου. Η καλλιέργεια των κυττάρων ομφαλίου λώρου (Τ ή μονοκυττάρων) AGA νεογνών, τυχαία επιλεγμένων ή κυττάρων περιφερικού αίματος ενηλίκου, με λεπτίνη είχε σαν αποτέλεσμα τη γονιδιακή έκφραση IL-2, INF-γ και IL-4 από τα κύτταρα του ομφαλίου λώρου, καθώς και από τα Τ κύτταρα του ενηλίκου όπως και την έκφραση IL-10 κυρίως από τα μονοκύτταρα αίματος ομφαλίου λώρου. Σημαντικά υψηλότερη γονιδιακή έκφραση INF-γ παρατηρήθηκε σε Τ κύτταρα ομφαλίου λώρου θήλεος τα οποία καλλιεργήθηκαν με λεπτίνη συγκριτικά με τα Τ κύτταρα ομφαλίου λώρου άρρενος. Συμπερασματικά, η παρουσία υψηλών συγκεντρώσεων λεπτίνης και INF-γ στον ορό αίματος ομφαλίου λώρου φυσιολογικών AGA νεογνών, καθώς και το γεγονός ότι η λεπτίνη μπορεί άμεσα να διεγείρει τη γονιδιακή έκφραση κυτταροκινών σε κύτταρα ομφαλίου λώρου (Τ και μονοκύτταρα) δείχνει ότι τα υψηλά επίπεδα λεπτίνης μπορούν ανεξάρτητα να επηρεάσουν το ανοσολογικό σύστημα των φυσιολογικών νεογνών και να συμβάλλουν στη Th1 διαφοροποίηση της ανοσολογικής απόκρισης. / Leptin is a hormone synthesized by adipocytes and other tissues, including the placenta, and it regulates food intake and energy expenditure, reproductive and immune functions. To investigate the role of leptin in neonatal immunity, we measured serum leptin and cytokine (INF-γ, TNF-α, IL-2, IL-4, IL-10, IL-12) levels in cord blood (cb) of 481 healthy neonates, born to healthy mothers, of which 317 were appropriately grown for gestational age (AGA) and 164 were large for gestational age (LGA). The median serum leptin concentration in the whole sample was 11.6 ng/ml. In 12% AGA neonates, leptin levels were well above average, with a median of 34 ng/ml. In 33% of these neonates (4% of the total sample) leptin levels ranged between 37.5-204 ng/ml; in this group, significantly elevated levels of serum IFN- were also found (mean 27.11 pg/ml, range 17.5-38.5 pg/ml). We then investigated whether leptin can independently influence cytokine gene expression by cb T-cells and monocytes (Mc). Culture of cb T-cells or Mc, isolated from randomly selected AGA neonates or adult peripheral blood mononuclear cells (PBMC), with leptin, resulted in upregulation of IL-2, IFN- and IL-4 gene expression in cb and adult T-cells and IL-10 gene expression mainly in cb-Mc. Significantly higher expression of IFN- occurred in female cb-T-cells cultured with leptin, compared with male cb-T-cells. In conclusion, the concurrent presence of high concentrations in both leptin and INF- in cb of healthy AGA infants, together with the fact that leptin can directly upregulate cytokine gene expression in cb T and Mc cells, indicate that abnormally high leptin levels can independently influence the immune system of healthy newborns, and may mediate gender differences in the development of a Th1 polarized immune response.
430

Avaliação do metabolismo ósseo em modelos de plasticidade ontogenética / Evaluation of bone metabolism in models of developmental plasticity

Lígia de Albuquerque Maia 21 February 2014 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / O aumento da prevalência da obesidade e osteoporose, bem como a identificação de mecanismos comuns que ligam a osteogênese e a adipogênese, sugerem que a obesidade e osteoporose podem ser distúrbios relacionados, e além disso, ambos podem ter suas origens no início da vida. Em 3 modelos diferentes de plasticidade ontogenética foi observado obesidade na vida adulta. Sendo assim, o objetivo deste trabalho foi investigar o impacto desses 3 modelos, o desmame precoce mecânico (DPM) e o farmacológico (DPF), e a supernutrição neonatal (SN) no tecido ósseo da prole durante o desenvolvimento. Para tanto, 2 experimentos foram realizados. No experimento 1, ratas lactantes foram divididas em 3 grupos: controle - os filhotes tiveram livre acesso ao leite durante toda a lactação; DPM - as mães foram envolvidas com uma atadura nos últimos 3 dias de lactação; DPF - as mães foram tratadas com bromocriptina (0,5 mg/duas vezes/dia) 3 dias antes do desmame padrão. No experimento 2, o tamanho da ninhada foi reduzido para 3 filhotes machos no 3o dia de lactação até o desmame (SN); o grupo controle permaneceu com 10 filhotes durante toda a lactação. Realizou-se absorciometria de raios-x de dupla energia, tomografia computadorizada, microtomografia computadorizada, teste biomecânico e análises séricas. Os dados foram considerados significativos quando P<0,05. No experimento 1, ao desmame, os filhotes DPM e DPF apresentaram menor massa corporal, massa gorda, densidade mineral óssea total (DMO), conteúdo mineral ósseo total (CMO), área óssea e osteocalcina sérica, e maior telopeptídeo carboxi-terminal do colágeno tipo I (CTX-I). O cálcio ionizado sérico foi menor apenas na prole DPM, a 25-hidroxivitamina D (25(OH)D) foi maior e o PTH menor apenas na prole DPF. Aos 180 dias, as proles DPM e DPF apresentaram maior massa corporal, maior massa de gordura visceral, hiperleptinemia, maior 25(OH)D e menor CTX-I. Ambos os grupos apresentaram aumento da DMO total, do CMO, da DMO da coluna vertebral e da área óssea aos 150 e 180 dias de idade. Nas avaliações ósseas individuais, as proles DPM e DPF também apresentaram aumento da DMO do fêmur e da vértebra lombar, da radiodensidade da cabeça femoral e do corpo vertebral; melhora da microarquitetura trabecular óssea e da resistência óssea. No experimento 2, observamos aumento da massa corporal, da massa gorda e da massa magra, do CMO e da área óssea no grupo SN desde o desmame até a idade adulta. Aos 180 dias, a prole SN também apresentou aumento da DMO total, da DMO do fêmur e da vértebra lombar, da radiodensidade da cabeça femoral e do corpo vertebral; melhora da microarquitetura trabecular óssea e da resistência óssea, maior osteocalcina e menor CTX-I. Demonstramos que, apesar de fatores de imprinting opostos, ambos os modelos causam melhora da massa, do metabolismo, da qualidade e da resistência óssea. Porém, parece que este efeito protetor sobre o tecido ósseo não é um resultado direto da programação deste tecido, mas sim consequência das alterações fisiopatológicas da obesidade programada pelos três modelos. / Nutritional changes during critical developmental periods are associated with chronic diseases in adulthood, a phenomenon known as developmental plasticity. Osteogenesis and adipogenesis have common mechanisms. In 3 different models of developmental plasticity, we observed programming for obesity. Thus, the aim of this study was to investigate the impact of these 3 models, mechanical early weaning (MEW), pharmacological early weaning (PEW), and early overnutrition (EO) upon offsprings bone tissue during development. Thus, the present study was divided into two experiments. In experiment 1, lactating rats were separated into 3 groups: control - pups had free access to milk; MEW - dams were involved with a bandage interrupting lactation in the last 3 days; PEW - dams were pharmacologically treated to block prolactin (0.5 mg bromocryptine/twice a day) 3 days before standard weaning. In experiment 2, litter size was adjusted to 3 male rats per litter (EO). Litter containing 10 pups per mother was control. Bone tissue was evaluated by dual-energy X-ray absorptiometry, computed tomography, microcomputed tomography, biomechanical tests and serum analyses. Data significant had P<0.05. In experiment 1, at weaning, MEW and PEW pups presented lower body weight, total body fat, total bone mineral density (BMD), total bone mineral content (BMC), bone area, serum osteocalcin and higher C-terminal cross-linked telopeptide of type I collagen (CTX-I). However, serum ionized calcium was lower only in MEW pups, 25-hydroxyvitamin D was higher and PTH was lower only in PEW pups. In adulthood, MEW and PEW groups presented higher body weight, visceral fat mass, 25-hydroxivitamin D, hyperleptinemia and lower CTX-I. Both groups presented higher total BMD, total BMC, spine BMD and bone area in 150 and 180 days. In individual bone evaluations, MEW and PEW offspring also showed higher femur BMD and fourth lumbar vertebra (L4) BMD, femoral head radiodensity and L4 vertebral body radiodensity, better bone trabecular microarchitecture and bone strength. In experiment 2, EO offspring showed higher body weight, fat mass, lean mass, BMC and bone area from weaning to adulthood. At 180 days, EO offspring also presented higher total BMD, femur BMD, L4 BMD, femoral head and vertebral body radiodensity, better bone trabecular microarchitecture and bone strength, higher osteocalcin and lower CTX-I. The three models lead to obesity and it seems that independent of the imprinting factors, there is a protective effect on bone tissue, which probably occurs as a result of different hormonal changes, that put together with the mechanical effect caused by excess of body fat mass, help us to explain the better bone health observed in these models of obesity.

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