吸煙是引起骨質疏鬆症的因素之一。臨床研究清楚表明吸煙者的骨密度降低，但其他干擾因素可能掩蓋了吸煙對骨頭的不良效果。使用動物模型用以研究吸煙和骨質疏鬆症之間是否有直接的因果關係與它潛在的機制是有必要的。為此，我們使用年輕和雌激素耗盡的小鼠作被動吸煙模型以及小鼠成骨細胞和破骨細胞株來作研究。 / 年輕的Balb/c小鼠暴露於2%或4% (v/v)的香煙煙霧中，代表中度和重度吸煙的人。骨代謝生物標誌物明顯增加，4%吸煙組在14週後股骨的微觀結構4%顯著下降，這相等於人類吸煙12年。此外，雌性Balb/c小鼠進行4%吸煙和/或卵巢切除術(OVX)。吸煙+OVX組增加血清中骨轉換指標水平。4%吸煙組的股骨生長板較薄。μ-CT數據進一步表明，相對骨體積(BV / TV)和結構模型指數(SMI)在吸煙組有顯著影響，而且在吸煙+ OVX組上有更大程度的影響。 / 在細胞研究中使用氯仿(CSE)和乙醇的香煙提取物(ESE)。CSE抑制小鼠細胞株RAW 264.7形成破骨細胞，並刺激小鼠成骨細胞株的分化和功能。這個與體內研究矛盾的結果暗示直接從煙霧中提取的化學成分並不是引起骨質疏鬆的元兇。影響骨代謝的很可能是其他從煙霧中生成的活性代謝物和一些吸煙引起的內源性激素物質。在吸煙引起的骨質流失中，這些代謝物或內源性物質可能是非常重要的。 / 有見及此，4%吸煙小鼠的血清用以研究其對成骨細胞和破骨細胞活動的影響。吸煙小鼠血清顯著降低在成骨細胞中鹼性磷酸酶(ALP)活性和鈣沉積，一些成骨細胞標記基因和蛋白表達均下降，而且 Wnt/β-catenin信號通路下調。此外，吸煙小鼠血清顯著增加形成破骨細胞的數量，組織蛋白酶K的基因和蛋白表達增加，在NF-κB和p-38 MAPK信號傳導途徑的信號分子表達增加。 / 總而言之，大量吸煙可能影響年輕小鼠和雌激素耗竭小鼠的骨代謝和微結構，通過類似的行動機制，人類也可能有同樣的骨疾病風險。這項研究揭示了吸煙導致的骨質疏鬆症在青少年和絶經後婦女的發病機制。這也給我們線索如何預防和治療與吸煙有關的骨骼疾病。這項研究還傳達了一個明確的信息：在年輕時應開始應控制吸煙。 / Cigarette smoking is one of the risk factors for osteoporosis. Clinical studies clearly showed that smokers have lower bone mineral density, but other confounding factors could mask the adverse actions of smoking on bones. Animal models are warranted to study the direct causal relationship between cigarette smoking and osteoporosis, and also the underlying mechanisms. In this regard, we used a mouse passive smoking model in both young and estrogen depleted mice, and the mouse osteoblast and osteoclast cell lines. / Young Balb/c mice were exposed to 2 or 4% (v/v) of cigarette smoke, similar to moderate or heavy smoking respectively in humans. Biomarkers for bone turnover were increased and bone microstructure of femur was significantly deteriorated after 4% smoking for 14 weeks which is similar to cigarette smoking for 12 years in humans. Furthermore, the effects of heavy smoking on ovariectomized mice were also investigated. Female Balb/c mice were subjected to 4% cigarette smoking and/or ovariectomy (OVX). Cigarette smoking together with OVX further increased the levels of bone turnover markers in serum. Femur growth plate was thinner in the 4% smoking group when compared to those in the SHAM- and OVX-operated groups. Micro-CT data further indicated that the relative bone volume (BV/TV) and structural model index (SMI) were significantly affected in the smoking groups, and to a greater extent in the 4% smoking + OVX group. / Chloroform (CSE) and ethanol smoke extracts (ESE) were used in cell studies. CSE suppressed the formation of osteoclasts, and stimulated the differentiation and function of mouse osteoblasts. These findings are contradictory to those found in in vivo study implying that chemical components directly extracted from cigarette smoke are not the culprits in causing bone disorder in animals. It is likely that other active metabolites from cigarette smoke and some endogenous hormonal substances released by cigarette smoking could affect bone metabolism. These active metabolites together with the endogenous bone hormones are perhaps crucial in smoking-induced bone loss in the body. / In view of this hypothesis, sera from 4% smoking mice were used to investigate their effects on osteoblast and osteoclast activities. It was found that the alkaline phosphatase (ALP) activity and calcium deposition in osteoblast were reduced significantly by the sera from smoking mice. Gene and protein expressions of some osteoblast markers were also decreased. The downregulation of Wnt/β-catenin signaling pathway was observed after the treatment with the serum obtained from the 4% smoking group. Moreover, the number of osteoclasts being formed was increased significantly by the smoking mouse serum. Cathepsin K gene and protein expressions were also induced. The increased expressions of the signaling molecules including NF-κB and p-38 MAPK were also observed. / In conclusion, heavy cigarette smoking could deteriorate bone metabolism and microstructures in young female and also estrogen depleted mice. The same kind of risk in bone disease may also apply to humans through similar mechanisms of action. This study sheds light in understanding the pathogenesis of smoking-induced bone disorders in teenagers and also postmenopausal women. It also gives us clues how to prevent and treat smoking related bone diseases. This study also conveys a clear message that cigarette smoking control should be started in young ages. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chan, Lok Yi Ruby. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 182-207). / Abstracts also in Chinese. / Chan, Lok Yi Ruby.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Pharmacology / Master / Master of Philosophy

Introduction: Tobacco smoking continues to raise serious concerns for health promotion practitioners and health bodies globally. It has been tagged the single largest cause of all premature deaths globally. Efforts at discouraging tobacco use especially among the youth are not only aimed at reducing smoking prevalence in the short term but at disrupting the chain of supply for the tobacco marketers who see the youth population as their source of replacement smokers. Measures to curb smoking prevalence currently rely heavily on policy regulation but there is need to have a holistic approach towards finding out what influences the youth to smoke in order to have relevant context-specific interventions to further tobacco control efforts. This study is aimed at ascertaining the risk influences for smoking behaviour amongst the youth in Southern Nigeria with specific focus on cultural/environmental, interpersonal and intrapersonal factors serving to increase smoking initiation and perpetuation as guided by the Theory of Triadic Influence (TTI). Method: Exploratory mixed methods research design was employed in carrying out this study. Qualitative interviews were conducted with 27 persons in 24 individual interviews (comprising of 18 young smokers aged 18 to 24 years, 4 political analysts and 2 community leaders) and 1 focus group discussion with 3 community leaders. A total of 550 youth aged between 18 and 24 years participated in the survey (quantitative) phase of this research. Non-probability sampling was used in recruiting participants for this study. Purposive sampling was used for the qualitative phase while multi-staged convenience sampling was used in the survey phase. Interpretative phenomenological analysis (IPA) with the aid of the software Nvivo 9 was used in analyzing the qualitative data while the software Statistical Package for the Social Sciences (SPSS) version 19 was used in the analysis of the quantitative data. Results: Qualitative and survey results show that there are an array of factors at various levels influencing the youth in southern Nigeria to view cigarettes as attractive and less harmful. At the cultural environmental level, there exist traditional practices in some parts of Southern Nigeria that make cigarettes easily accessible to the youth. Contact with cigarettes as a minor was found to be the best predictor of smoking among other cultural factors involving tobacco use while exposure to second hand smoke was the best predictor of smoking. With an absence of a functional national tobacco control law presently, cigarette is cheap, easily accessible to young people and tobacco manufacturers and marketers still promote their businesses in many ways which target the youth. At the interpersonal level, youth were influenced majorly by their peers to initiate smoking but indirectly by parents, older sibling and role models who smoke. At the intrapersonal level, youth were found to smoke for a variety of reasons ranging from wading off depression, coping with social stress and wanting to live up to the expectations of friends. Youth’s knowledge about the effect of smoking on health and well-being did not translate to a desire to quit smoking. Conclusion/recommendations: The Nigerian government needs to take urgent steps to address the tobacco question in the country through policy formulation and implementation. There is need to raise more awareness in the population on the dangers of smoking. Cessation clinics are also needed to help those who desire to quit smoking. Cultural activities involving the use of cigarettes and other tobacco products need to be properly addressed through the right channel to ensure this practice is stopped. A theoretical model explaining the risk influences for smoking among the youth is presented and suggestions are made with regards to a re-categorization of constructs in the theory of triadic influence which guided this study. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.

The purpose of this study was to determine the effects of graduated exercise at the piano on the pianist's cardiac output, forearm blood flow, heart rate, and blood pressure. Also considered were the effects of piano practice conditioning, general cardiovascular conditioning, and acute cigarette smoking on the aforementioned parameters during and after graduated piano exercise.Fifteen adult pianists participated in the study. The piano exercises consisted of bilateral scales played in eight three-minute stages. Tempo was constant within stages but increased with each new stage. Cardiac output and forearm blood flow were monitored by electrical impedance utilizing a tetrapolar electrode-placement system.FindingsCardiac output, forearm blood flow, heart rate, and systolic blood pressure generally increased proportionally to exercise intensity and returned to basal levels within a five-minute recovery period.ConclusionsStrenuous piano exercise stresses the body in general, not just the active forearm muscles.The stress load placed on the heart by piano playing can be at least as great as that produced by a brisk walk.Piano playing can generate an oxygen debt in the forearm muscles.Conditioning of forearm muscles through regular piano practice results in training effect for piano playing in those muscles.Pianists who participate regularly in quality aerobic exercise programs generally begin and end piano exercise with lower heart rates than those who do not exercise. Frequently, they increase heart rates to a lesser extent during exercise and settle into steady postexercise rates more quickly as well.Both regular piano practice and general cardiovascular conditioning gained through quality aerobic exercise contribute to increased piano-playing endurance.Acute smoking increases cardiac outputs and heart rates of pianists resulting in higher levels of cardiac work during piano exercise.During piano exercise, acutely smoking pianists require greatly increased forearm blood flows to meet muscle needs.

The structural and functional integrity of a developing and maturing fetal and neonatal lung is critically dependent on carbohydrate metabolism. The energy derived from carbohydrate metabolism is utilized during the processed of cell growth and development. It is reported that maternal nicotine exposure during pregnancy and lactation results in the irreversible inhibition of glycolysis, for which no mechanism is currently proposed and a significant increase in glucose turnover. The principal objective of this thesis was to determine the influence of maternal nicotine exposure during gestation and lactation on the isoenzyme patterns and transcript levels of the selected enzymes in developing neonatal rat lung, in an attempt to elucidate the mechanism of inhibition of glycolysis observed.

No description available.

To determine the relationship of tobacco and marijuana smoking to levels of cadmium and zinc manifested in hair samples, a study was conducted at Portland State University using atomic.absorption spectrophotometry. 97 adult student volunteers participated in the main study.

Nicotine titration was studied in cigarette smokers not interested in cutting down or quitting smoking. Forty smokers were classified as high nicotine dependent (n=20) and low nicotine dependent (n=20) using a validated tolerance questionnaire. Subjects were randomized into baseline (n=10) or nicotine fade conditions (n=10) within their dependency group. Subjects in the baseline conditions smoked their preferred brand of cigarette throughout the experiment. Smokers in the fade conditions switched to a reduced nicotine brand in the latter half of the procedure. Multiple in vivo and in vitro measures of smoking rate and topography were collected over a four day period. Based on analyses of these data, it was concluded that no compensatory changes in smoking behavior occurred that were clearly attributable to nicotine titration. It was found that smokers classified as high nicotine dependent smoked more intensively that low dependent smokers. The implications of these findings given the design and experimental controls employed in this experiment are discussed, and directions for future research explored. / M.S.

This study (1) quantitatively compared steroid production in cultured Y-l mouse adrenal tumor cells exposed to Camel and Carlton-smoke derived residues, and (2) localized the effects in the cell. Basal steroid production was increased by Camel residues but not by Carlton, while ACTH stimulation was interfered with by both residues. Camel basal stimulation was comparable to that of cAMP, and was abolished by Cytochalasin D. The stimulation was also comparable to that of cholera toxin, which activates adenyl cyclase. Results indicate that residue components dissolve in the membrane stimulating adenyl cyclase at a point similar to or before that utilized by cholera toxin for its stimulating effect.