Dietary fat, body weight, and cancer: contributions of studies in rodents to understanding these cancer risk factors in humans

Understanding diet and energy balance as risk factors for breast, colon, and other cancers requires information on the contribution of each factor and of interactions among factors to cancer risk. Rodent models for breast cancer provide extensive data on effects of dietary fat and calories, energy balance, body weight gain, and physical activity on tumor development. Analyses of the combined data from many studies have shown clearly that quality and quantity of dietary fat and energy balance contribute independently to increased mammary gland tumorigenesis. These findings were seen in female rats fed diets high in fat (35-40% of calories) compared to rats fed control diets, with approximately 10% of calories as fat (Fay and Freedman, 1997, Breast Cancer Res. Treat. 46, 215-223). The methods used permit comparison of experimental and epidemiological data, and they may be useful in extrapolating between species and developing public health recommendations. In addition to the contributions of lifetime-diet composition, intake, energy balance, and physical activity to cancer risk, there are questions about the timing and duration of alterations in these factors and about the "dose-response" characteristics of cancer risk to the factors. Endocrine mechanisms may be significant in mammary gland tumor risk, but experimental and epidemiological data indicate that cancers at other sites, such as colon and liver, also are influenced by the factors listed. Other diet and lifestyle factors that influence energy, or specifically fat, metabolism may also affect risk for cancers that are promoted by increased intake of fat and calories. Studies of separate and interactive effects of dietary fat, black tea, weight gain, and mammary gland tumorigenesis (Rogers, et al, 1998, Carcinogenesis 19, 1269-1273) have been analyzed. Using adjustment of carcinogenesis endpoints for body weight, tumor burden, and latency, they were found to be related to weight gain within treatment groups in 2 of 3 experiments.      

Successful pregnancy in transfusion-dependent thalassaemia

Successful pregnancy in a transfusion-dependent thalassaemic patient receiving subcutaneous desferrixaomine is reported. This is the first such case to be described.     

Hypoaldosteronism in three sibs due to 18-dehydrogenase deficiency

Three sibs all presented in the early neonatal period with a salt-losing syndrome. The salt-losing form of congenital adrenal hyperplasia was diagnosed and appropriate treatment with glucocorticosteroids, mineralocorticosteroids, and additional dietary salt started. Although early life was maintained with difficulty, with age all 3 children required decreasing amounts of replacement steroids to maintain normal plasma electrolyte balance. They were reinvestigated at the ages of 15 years and 8 years (twins), when cortisol synthesis and metabolism proved normal, but aldosterone synthesis was blocked by deficiency of 18-dehydrogenase. Rational treatment of these cases of a salt-losing syndrome in which aldosterone synthesis alone is blocked due to lack of the enzyme 18-dehydrogenase requires the administration of a mineralocorticosteroid drug only. Since deoxycorticosterone (acetate or pivalate) requires intramuscular administration, as life-long therapy oral fludrocortisone is preferable. Although fludrocortisone has glucocorticoid activity, the "hydrocortisone equivalent" effect of the small dosage used was unlikely to inhibit either pituitary corticotrophin or growth hormone production.     

Biomarkers of periodontal inflammation in the Australian adult population

Background:  Several inflammatory biomarkers are implicated in the pathogenesis of periodontitis including interleukin-1β (IL-1β) and C-reactive protein (CRP). This study investigated the presence of these factors in gingival crevicular fluid (GCF) and their relationship to clinical and social determinants of periodontitis in the Australian population.
Methods:  Equal numbers of periodontitis cases and non-cases were sampled during oral epidemiologic examination in the National Survey of Adult Oral Health. GCF was sampled from four sites where probing pocket depth (PPD) and recession were recorded. From these, IL-1β and CRP were quantified by ELISA and the log amount of GCF IL-1β (pg) per person and the proportion of adults with detectable CRP was computed.
Results:  Periodontitis cases (n = 511) had significantly higher levels of IL-1β and CRP than non-cases (n = 562). PPD, clinical attachment loss, plaque and gingivitis indices were positively associated with elevated levels of both biomarkers. Levels of both were positively associated with age, low socio-economic position and non-Australian birth.
Conclusions:  The presence of IL-1β and CRP in GCF are associated with periodontal disease parameters within the Australian population. The levels of both biomarkers are influenced by age, education and eligibility for public dental care.     

雷米普利和氯沙坦对动脉粥样硬化早期形成的影响

目的 :研究雷米普利和氯沙坦对动脉粥样硬化 (atherosclerosis,AS)早期形成的影响。方法 :将 4 4只金黄地鼠随机分为 5组 ,分别给常规饲料 (对照组 )、高脂饲料 (含 10 %椰子油和 0 .0 5 %胆固醇 )、高脂饲料加雷米普利 (2mg·kg 1)、高脂饲料加氯沙坦 (10mg·kg 1)和高脂饲料加雷米普利 (2mg·kg 1)与氯沙坦 (10mg·kg 1)处理12周 ,测定血压、血脂、AS斑块面积和肝组织中胆固醇含量的变化。结果 :数据表明雷米普利和氯沙坦不论是单独应用还是联合应用均能有效降低平均动脉压 (P <0 .0 0 1)和肝组织中胆固醇的含量 ,雷米普利能显著降低血浆中甘油三酯的水平 (P <0 .0 5 ) ,结果还显示雷米普利与氯沙坦联合应用能提升血浆中高密度脂蛋白 (P <0 .0 5 ) ,各药物处理组的AS斑块面积有不同程度降低但无统计学意义。结论 :雷米普利与氯沙坦具有一定的抑制AS形成作用 ,其机制可能与降低血压和改变脂代谢有关。     

Tumbling and spaceflight: the Gemini VIII experience

A malfunctioning orbital flight attitude thruster during the flight of Gemini VIII led to acceleration forces on astronauts Neil Armstrong (commander) and David Scott (pilot) that created the potential for derogation of oculo-vestibular and eye-hand coordination effects. The spacecraft attained an axial tumbling rotation of 50 rpm and would have exceeded this had not the commander accurately diagnosed the problem and taken immediate corrective action. By the time counter-measure controls were applied, both astronauts were experiencing vertigo and the physiological effects of the tumbling acceleration. Data from the recorders reveal that one astronaut experienced -Gy of 0.92 G-units, and the other +Gy of 0.92 for approximately 46 s. Both received a -Gz of 0.89 G-units from the waist up with a +Gz of 0.05 from the waist down. A substantial increase of time and/or an increase in rpm would ultimately have produced incapacitation of both astronauts. NASA corrected the Gemini thruster problem by changing the ignition system wiring. Future space-craft undertaking long-term missions could be equipped with unambiguous thruster fault displays and could have computer-controlled automatic cutoffs to control excessive thruster burns.