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Fractures and bone mass in urban South African children of different ethnic backgroundsThandrayen, Kebashni 25 August 2014 (has links)
Aims:
1) To determine the incidence or rates of fractures, the common sites of fractures, the
causes of fractures and grades of trauma causing fractures in urban South African
children of different ethnic groups from birth until 17/18 years of age.
2) To investigate the association between fracture prevalence, bone mass and physical
activity in South African children.
3) To assess associations of fracture prevalence and bone mass in adolescents with
maternal fracture history and bone mass and sibling fracture history.
Design:
Using the Birth to Twenty longitudinal cohort of children, we obtained retrospective
information on fractures and their sites from birth to 14.9 years of age on 2031 participants.
The ethnic breakdown of the children was black (B) 78%, white (W) 9%, mixed ancestry
(MA) 10.5% and Indian (I) 1.5%.
Using the Bone Health cohort of the Birth to Twenty longitudinal study, we retrospectively
obtained information of lifetime fractures until age 14.9 years in 533 subjects. Bone mass
(measured by DXA), anthropometric data, physical activity scores and skeletal maturity were
obtained at age 10 and 15 years. Comparisons were made between those who did and did not
fracture within the same sex and ethnic groups.
The third component of the thesis utilized data from 1389 adolescent-biological mother pairs
of the Birth to Twenty (Bt20) longitudinal study. Questionnaires were completed on
adolescent fractures until 17/18 years of age and on sibling fractures. Biological mothers
completed questionnaires on their own fractures prior to the age of 18 years. Anthropometric
and bone mass data on adolescent-biological mother pairs were collected.
Results:
Twenty two percent of children had sustained a fracture one or more times during the first 15
years of life (males 27.5% and females 16.3%; p<0.001). The percentage of children
fracturing differed between the ethnic groups (W 41.5%, B 19%, MA 21%, I 30%; p<0.001).
Of the children reporting fractures, 20% sustained multiple fractures. The most common site
of fracture was the upper limb (57%).
In the second component of the thesis, white males who fractured were found to be
significantly taller (10 years p < 0.05), more physically active (15 years p < 0.01) and had
higher lean body mass (10 years p=0.001; 15 years p<0.05) than those who did not fracture;
while white females, who fractured, were fatter (10 and 15 years p< 0.05), than their nonfracturing
peers. White males who fractured had greater BA (bone area) and BMC (bone
mineral content) at most sites at 10 and 15 years; BA and BMC were no different between
fracturing and non-fracturing children in the other ethnic groups. No anthropometric or bone
mass differences were found between black children with or without fractures.
The third component of the thesis showed that an adolescent’s risk of lifetime fracture
decreased with increasing maternal lumbar spine (LS) BMC (24% reduction in fracture risk
for every unit increase in maternal LS BMC Z-score) and increased if they were white, male
or had a sibling with a history of fracture. Adolescent height, weight, male gender, maternal
BA and BMC, and white ethnicity were positive predictors of adolescent bone mass. White
adolescents and their mothers had a higher fracture prevalence (adolescents: 42%, mothers:
31%) compared to the black (adolescents: 20%, mothers: 6%) and mixed ancestry
(adolescents: 20%, mothers: 16%) groups.
Conclusion:
More than twice as many South African white children fracture compared to black and mixed
ancestry children. This is the first study to show ethnic differences in fracture rates among
children; a pattern that is similar to that found in South African postmenopausal women. The
factor associated with fractures in white boys appears to be participation in sports activities,
while in white girls obesity appears to play a role. We were unable to find any factors that
could explain fractures in black children. Unlike the findings of some other studies, fractures
in these children were not associated with lower bone mass or reduced skeletal size.
Maternal bone mass also appears to play a role in determining fracture incidence in children,
as the mother’s bone mass has a significant inverse association with their off-springs’ fracture
risk throughout childhood and adolescence. Furthermore, there is a strong familial component
in fracture risk among South African adolescents and their siblings, as evidenced by the
increased risk of fracture in siblings of index children who have fractured during childhood
and adolescence.
Differences in fracture rates and bone mass between families and individuals of different
ethnic origins may be due to differing lifestyles and/or genetic backgrounds.
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Role of TRAF2/6 in tumour growth and bone metastases associated with breast cancerPeramuhendige, Pushpabhani Prabha January 2016 (has links)
Tumour necrosis factor receptor associated factors (TRAFs) play a key role in signal transduction in mammalian cells. Several members of the TRAF family have been identified but only TRAF2 and TRAF6 are implicated in the regulation of both osteoclastic bone resorption and breast cancer. Here I studied the role of TRAF2 and TRAF6 in breast cancer induced osteoclastogenesis and osteolysis. I observed that TRAF2, but not TRAF6, is highly expressed in a highly metastatic bone-tropic clone of the human MDA-MB-231-BT (MDA-231-BT) breast cancer cells when compared to parental MDA-MB-231 (MDA-231) cells. Targeted knockdown of TRAF2, but not TRAF6, in both parental MDA-231 and bone-tropic MDA-231-BT breast cancer cells by siRNAs markedly reduced cell migration and significantly reduced the ability of these cells and their conditioned medium to induce osteoclast formation in RANKL stimulated bone marrow cultures. Encouraged by these data, I generated stable parental MDA-231 and bone-tropic MDA-231-BT breast cancer cell lines overexpressing TRAF2 using a retroviral approach. Then, I went on to show that overexpression of TRAF2 in parental MDA-231 cell line significantly stimulated directed cell migration and 3D invasion in vitro. Bone-tropic MDA-231-BT breast cancer cells over expressing TRAF2 or their conditioned medium were significantly effective in enhancing RANKL induced osteoclast formation in vitro. Mechanistic studies in parental MDA-231 and bone-tropic MDA-231-BT breast cancer cells revealed that over-expression of TRAF2 enhanced cell migration and osteoclastogenesis via a mechanism that involves the activation of the breast cancer oncogene IKKepsilon (IKKε) coupled with significant increase in levels of Vascular endothelial growth factor (VEGF). Ex vivo studies in human MDA-231-mouse calvaria organ co-cultures showed that conditioned medium obtained from MDA- 231 cells enhanced calvarial osteolysis. In vivo studies showed that overexpression of TRAF2 in the human breast cancer cells MDA-231 enhanced tumour incidence and tumour volume after orthotopic injection and exacerbated osteolysis after supracalvarial injection of conditioned medium from these cells. In conclusion, our studies showed that the TRAF2/IKK/VEGF axis in breast cancer cells regulates breast cancer cell motility in vitro, osteoclastogenesis in vitro and osteolysis ex vivo and in vivo. However, the role of TRAF2 in bone metastasis associated with breast cancer will require further in vivo investigation.
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Infectious complications in bone marrow transplant recipients袁國勇, Yuen, Kwok-yung. January 1998 (has links)
published_or_final_version / Medicine / Master / Doctor of Medicine
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Consumer and sensory perceptions of black bone discoloration in broiler chickensYu, Debrah Unknown Date
No description available.
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Consumer and sensory perceptions of black bone discoloration in broiler chickensYu, Debrah 06 1900 (has links)
Consumers and Canadian poultry processors were interviewed to understand the overall perception of bone-in chicken meat and to gain insight on the defect of black bone discoloration, a color defect that appears in cooked bone-in chicken. Through the consumer science technique of laddering, food safety, eating quality, price, health and convenience were revealed as the most important values associated with chicken meat. Poultry processors agreed upon the importance of food safety. Black bone discoloration did not greatly influence consumer acceptance of broiler meat, nor did it appear to negatively impact the poultry industry as complaints were reported rarely. Modifying broiler bone growth rate through dietary treatments did not significantly (P>0.05) alter the sensory properties of the meat or reduce the incidence of discoloration. Overall, black bone discoloration is not perceived as a major problem for the poultry industry in Canada. In order to maintain consumer demand, poultry producers should focus on the food safety aspect of their products. / Food Science and Technology
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Bone healing after implantation of bone substitute materials : experimental studies in estrogen deficiency /Öberg, Sven, January 2003 (has links)
Diss. (sammanfattning) Umeå : Univ., 2003. / Härtill 5 uppsatser.
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The use of anorganic bone to alter jaw morphology in dogs submitted in partial fulfillment of the requirements ... oral surgery /Thompson, Seth C. January 1959 (has links)
Thesis (M.S.)--University of Michigan, 1959.
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Towards an injectable bone graft substitute evaluation of sodium alginate microcapsules for bone tissue engineering /Abbah, Sunny Akogwu. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
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On bone cuttingToksvig-Larsen, Søren. January 1992 (has links)
Thesis (doctoral)--Lund University, 1992. / Added t.p. with thesis statement inserted. Booklet of related papers inserted.
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Bone mass in young adults determinants and fracture prediction /Düppe, Henrik. January 1997 (has links)
Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.
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