Lifestyle and blood pressure levels in male twins in Utah

Healthy male monozygotic (MZ) and dizygotic (DZ) twin pairs (MZ pairs = 77; DZ pairs = 88) were studied to assess the effect of dietary intake, physical activity, physical fitness, body mass index (BMI), sum of the triceps and subscapular skinfold measurements, alcohol and caffeine consumption, and smoking patterns on blood pressure. Data on physical activity, detailed dietary intake, medical history, and demographics were obtained from a questionnaire. A bicycle ergometer was used to estimate level of fitness; other medical information was ascertained from physical examination. After normalizing the study variables, intraclass correlations for BMI and the sum of the triceps and subscapular skinfold measurements were higher in MZ than in DZ twin pairs (BMI: MZ r = 0.76, DZ r = 0.48; skinfolds: MZ r = 0.73, DZ r = 0.28), as were VO2max(MZ r = 0.63, DZ r = 0.25) and post-bike heart rate (MZ r = 0.69, DZ r = 0.19). Both systolic (SBP) and diastolic blood pressure (DBP) had high heritability estimates (SBP = 0.60, and DBP = 0.66). Using factor analysis, four major lifestyle factors were identified and categorized as: 1) dietary intake; 2) a factor heavily weighted by cigarette smoking, alcohol and caffeine consumption; 3) fatness; 4) physical activity and physical fitness. Adjustment for these factors did not alter heritability estimates for either SBP or DBP.     

锰对雄性小鼠血清性激素水平的影响

目的 探讨锰暴露对雄性小鼠血清性激素分泌的影响。 方法 选用健康雄性昆明小鼠48只,随机分为对照组和低、中、高染锰组。各组小鼠分别腹腔注射生理盐水、12.5、25.0、50.0 mg/kg MnCl₂,注射容量5 ml/kg,每天染毒1次,持续14 d,最后一天染毒24 h后处死小鼠,测量体重、睾丸和附睾的重量,腹主动脉采血,离心后取血清用酶联免疫试剂盒检测促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)、卵泡刺激素(folide-stimulating hormone,FSH)、黄体生成素(luteinizing hormone,LH)和睾酮(testosterone,T)的水平。HE染色观察下丘脑神经元细胞组织形态的改变。 结果 与对照组相比,各染锰组小鼠体重、睾丸和附睾脏器系数差异无统计学意义(P>0.05),而高锰组血清中GnRH、FSH和LH含量显著升高至68.22 ng/L、11.43 U/L、2 055.82 pg/ml(P<0.05),T水平明显降低至81.25 nmol/L(P<0.05)。HE染色发现对照组可见结构清楚,排列规整,核膜清晰,染锰组逐渐形态紊乱,胞体皱缩,细胞周围间隙增大。 结论 锰暴露可引起雄性小鼠血清性激素分泌异常以及下丘脑组织形态受损,GnRH、FSH、LH明显升高,睾酮降低。     

LISREL modeling of high density lipoprotein cholesterol (HDL) levels in male twins

Based on the LISREL modeling approach for data from monozygotic (MZ) and dizygotic (DZ) twins [Heath et al., 1989; Neale and Cardon, 1992], the hypothesized variance of the logarithm of high density lipoprotein cholesterol due to additive genetic factors was estimated to equal 19% for males. Unobserved common environment accounted for 32% of the variance of log HDL. Both estimates controlled for body mass, alcohol consumption, and smoking. The model had very strong goodness-of-fit indices. © 1993 Wiley-Liss, Inc.     

Risk factors for atherosclerosis in twins

We performed multivariate genetic analyses of cardiovascular risk factors from two sets of data on US and Australian female twins. Similar models for body-mass index (BMI), serum low density (LDL) and high density (HDL) lipoproteins, including age as a covariate, were fitted successfully to both groups. These suggested that BMI, or genes responsible for a significant proportion of the variance of BMI, explained correlations between lipid subfractions, as well as those between blood pressure and lipid subfractions, especially HDL. © 1993 Wiley-Liss, Inc.     

Regulation of male sex hormone levels by soy isoflavones in rats

Several studies have suggested that soybean intake is associated with a lower risk of prostate cancer. However, the mechanism of prostate cancer prevention by soybeans remains unclear. Because prostate cancer is reported to have an association with an increased level of dihydrotestosterone (DHT) and soybean isoflavones are known to inhibit 5 alpha-reductase, which is involved in the conversion of testosterone to DHT, the effects of soybean extract and isoflavones on the plasma levels of male sex hormones were investigated using male rats. In Experiment I, Sprague-Dawley rats were fed diets with and without soy flour; in Experiment II, rats were fed diets containing 2% soy methanol extract or 0.2% semipurified isoflavones or a control diet. The study showed a reduction of plasma DHT along with an increase in total plasma androgen in rats fed soy flour or semipurified isoflavones for 1 wk. These results suggest that soy isoflavone intake may reduce plasma DHT level.     

Lifestyle factors in monozygotic and dizygotic twins

In examining genetic influences on biological variables using twins, it may be important to examine the distribution between and within twin pairs of demographic and lifestyle factors that may themselves affect the biological variable being studied. We explored the distribution of demographic and lifestyle factors that may affect blood lipid levels or ischaemic heart disease (IHD) risk among a sample of 106 monozygotic (MZ) and 94 like-sex dizygotic (DZ) twin pairs. In our sample, MZ twins were statistically significantly different from DZ twins only in marital status, cigarette smoking habits, and the ratio of polyunsaturated to saturated fat (P:S ratio) in their dietary intake. The latter variable was among many dietary variables examined (using 4-day weighed food diaries), and the size of the difference in intake was small. When comparisons were made of the similarities within twin pairs, we found members of MZ twin pairs to be statistically significantly closer than DZ twins in educational achievement, occupation, cigarette smoking, and exercise habits, and the number of days a week on which alcohol was consumed. These last three variables were consistently closer among twins with closer contact than among those with a smaller degree of current shared environment. For 12 of the 13 nutrients examined, the within-pair correlations were higher for MZ than for DZ twins, although our test for significant genetic variance showed statistical significance only for intake of complex carbohydrates. We conclude that MZ twins share demographic and lifestyle factors that might influence the risk of IHD and blood lipid levels to a greater degree than do DZ twins, although it is difficult to say if these similarities in lifestyle result from genetic influences or not. Nevertheless, ascribing differences between correlations in MZ and DZ twin pairs for lipid levels as being purely "genetic"--as implicit in conventional measures of heritability--is likely to overestimate the influence of genetic factors.     

1.1⁃二氨基⁃2,2⁃二硝基乙烯对雄性大鼠性激素水平的影响

为评价1,1-二氨基-2,2-二硝基乙烯(FOX-7)对雄性大鼠性激素水平的影响,将受试物采用3个剂量(199.1、99.6、49.8 mg/kg)染毒,同时设溶剂对照组(4%淀粉溶液)。将40只健康SPF级雄性SD大鼠随机分为4组,每组10只,每日固定时间采用经口灌胃方式染毒,染毒容量为1 ml/100 g,连续14 d。于第0天、第7天、第14天称量大鼠体重,禁食12 h后,于第15天对大鼠进行腹主动脉采血,使用ELISA试剂盒检测雌二醇(E2)、促卵泡素(FSH)、黄体生成素(LH)、睾酮(T)、促性腺激素释放激素(GnRH)含量。结果显示,与溶剂对照组比较,FOX-7高剂量组大鼠第7天和第14天体重显著下降(P0.05),性激素T、FSH、LH、E2和GnRH含量均显著降低(P0.05)。提示高剂量的FOX-7可能会引起雄性大鼠性激素水平紊乱,生殖系统损伤。     

Lifestyle and dietary factors in relation to prostate cancer risk

Abstract

The aim of the present study was to determine the association between the socio-demographic, lifestyle factors, and dietary habits with the risk of prostate cancer (PC) in a case–control study of Spanish men. None of the socio-demographic, lifestyle or dietetic variables was found predictors of PC risk. Body mass index was associated with an increased risk for aggressive PC and fruit consumption with lower Gleason scores, thus less aggressive cancers. Nonetheless, after applying Bonferroni correction, these variables were not still associated with PC aggressiveness. More adequately, powered epidemiological studies that measure the effect of lifestyle and dietary intake in PC risk and aggressiveness are warranted to further elucidate the role of these modifiable factors on PC etiology.     

镉接触工人体内血清性激素水平的变化

目的 探讨镉接触工人体内血清性激素水平的变化及其机制。方法 选取南方某冶炼厂镉接触工人及当地健康男性为调查对象,经空气采样测定各车间空气中镉的浓度,用原子吸收分光光度法测定尿镉,并经肌酐校正作为调查对象体内镉负荷的生物标记物;同时测定工人体内性激素水平,并进行镉接触的剂量－效应评定。结果 在控制年龄等混杂因素后,血清睾酮水平随镉接触水平的增高而呈升高趋势,其中尿镉为10．9－21．9μmol/mol肌酐及＞21．9μmol/mol肌酐组的睾酮水平分别为：13．00nmol／L和11．37nmol／L,与0．0－2．2μmol/mol肌酐组的9．31nmol／L比较,差异有显著性;电解车间及尿镉＞21．9μmol/mol肌酐组人的血清黄体生成素水平分别为4．11U／T和4．32U／L,显著同于对照组的2．52U／L和尿镉0．0－2．2μmol/mol肌酐组的2．64U／L。结论 镉接触能引起工人血清性激素水平的变化。     

毒死蜱对雄性大鼠生精功能及相关激素水平影响

目的 探讨毒死蜱对雄性大鼠生精功能和血清激素水平的影响.方法 选择21 d龄无特定病原体级雄性Wister大鼠随机分成3个实验组和1个对照组,每组10只.实验组灌胃给予毒死蜱,剂量为2.7、5.4、12.8 mg·kg-1·d-1;对照组给予等量蒸馏水稀释的吐温80溶液.染毒90d后,测定各组大鼠睾丸、附睾和前列腺-精囊腺等脏器系数、检测附睾尾精子数量、精子活动率和精子崎形率以及血清中性激素水平.结果 高、中剂量组精子数量减少、精子畸形率升高、精子活力显著降低(P<0.05).高、中剂量组血清睾49 (T)水平降低,促卵泡刺激素(FSH)升高(P<0.05).不同组别血清中黄体生成素(LH)及雌二醇(E2)水平比较,差异无统计学意义(P>0.05).结论　毒死蜱对雄性大鼠有明显的生殖毒性,可影响雄性大鼠生精功能和血清中性激素水平.     

Endogenous sex hormone levels and breast cancer risk

Sex-steroid hormones are a major determinant of the risk of breast cancer. We evaluated the relationship between obesity and endogenous estrogen levels in 79 healthy, postmenopausal women. Thirty-nine of the women were siblings of patients with postmenopausal-onset breast cancer; the remaining women were age-matched (+/- 10 yr) controls. Our hypothesis was that the siblings of the breast cancer patients would weigh more and that this excess weight would lead to higher serum estrone levels. The choice of unaffected family members of breast cancer patients reduces the concern that results may have been influenced by the cancer rather than antecedent to its development. Our findings demonstrated a statistically significant excess estrone level in the siblings compared to the controls (58.9 vs 47.8 pg/ml, P = 0.005). The siblings weighed 4.3 kg more than the controls. Matched pairs analysis (sibling-control), adjusting for weight, also showed significant differences in serum estrone levels. These differences were observed despite comparability in dietary intake, medication use, and personal medical history. These findings represent the first time that higher estrogen levels have been measured in siblings of postmenopausal breast cancer patients. This observation may represent an important link in our understanding of the relationship between genetic and environmental risk factors of breast cancer. One approach to subsequent genetic studies of breast cancer may be to focus on the possible biological determinants such as sex-steroid hormone level receptors, oncogenes, and gene products and not on the "familial aggregation" of breast cancer.     

A systematic review of the effect of diet in prostate cancer prevention and treatment

Dietary therapy has been proposed as a cost effective and noninvasive means of reducing the risk of prostate cancer (PC) and its progression. There is a large volume of published studies describing the role of diet in the prevention and treatment of PC. This article systematically reviews the data for dietary-based therapy in the prevention of PC, as well as in the management of patients with PC, aiming to provide clarity surrounding the role of diet in preventing and treating PC. Although conclusive evidence is limited, the current data are indicative that a diet low in fat, high in vegetables and fruits, and avoiding high energy intake, excessive meat, excessive dairy products and calcium intake, is possibly effective in preventing PC. However, caution must be taken to ensure that members of the public do not take excessive amounts of dietary supplements because there may be adverse affects associated with their over consumption. The dietary recommendations for patients diagnosed with PC are similar to those aiming to reduce their risk of PC.     

Genetic analysis of sex and generation differences in plasma lipid,lipoprotein, and apolipoprotein levels in adolescent twins and their parents

In a sample of Dutch families consisting of parents aged 35–65 years and their twin offspring aged 14–21 years, a significant difference between generations was observed in phenotypic variances and in genetic heritabilities for plasma levels of total cholesterol, triglycerides, high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol, and apolipoproteins (apo) A1, A2, B, and E. For all traits parents were more variable than their offspring. This increase in phenotypic variance was best explained by a genetic model in which individual specific environmental variance increased with increasing age. Genetic variance was the same across generations for nearly all traits except triglycerides and apoE, for which a decrease in genetic variance was observed. This model led to large intergenerational differences in genetic heritabilities. Heritabilities for children were between 65 and 87%, while heritabilities for their parents were between 10 and 50%. No evidence was found for effects of a shared family environment. © 1996 Wiley-Liss, Inc.     

双生子儿童体格发育指标遗传度分析

目的分析儿童体格发育指标的遗传度，探讨遗传与环境因素对各发育特征的影响程度。方法测量218对6～13岁同性别双生子的9项体格发育指标，分性别对年龄进行校正后，用组内相关系数法计算各指标遗传度。结果多数指标的遗传度在60％以上，且在一定程度上存在性别差异。结论遗传因素对儿童发育起主要作用，性别对体重、头长和头宽遗传度的影响最为明显。     

20例男性2型糖尿病患者性激素结合球蛋白和性激素的测定及相关因素分析

目的 研究男性2型糖尿病患者性激素结合球蛋白（SHBG）和性激素的变化及相关因素分析。方法 检测了20例男性2型糖尿病患者（糖尿病组）和10例糖耐量正常的男性（对照组）血清SHBG、睾酮（T）和雌二醇（E2）浓度。结果SHBG、T和E2浓度在糖尿病组分别为（62.50±27.08）nmol／L、（48.41±9.96）nmol／L和（150.84±96.81）pmol／L，而在对照组分别为（74.16±32.30）nmoL／L、（50.55±12.39）nmol／L和（166.03±121.55）pmol／L，三个指标两组间比较差异均无统计学意义（P〉0.05）。糖尿病组组内相关因素分析发现，SHBG与年龄呈正相关（r=0.54，P〈0.01），与体重指数（BMI）呈负相关（r=-0.46，P〈0.01），并与空腹胰岛素呈负相关（r=-0.48，P〈0.01）。逐步回归分析发现，年龄和BMI对SHBG影响最大。结论2型糖尿病本身对SHBG和性激素浓度无明显影响，而年龄和BMI是其独立影响因素。     

20例男性2型糖尿病患者性激素结合球蛋白和性激素的测定及相关因素分析

目的 研究男性2型糖尿病患者性激素结合球蛋白(SHBG)和性激素的变化及相关因素分析.方法 检测了20例男性2型糖尿病患者(糖尿病组)和10例糖耐量正常的男性(对照组)血清SHBG、睾酮(T)和雌二醇(E2)浓度.结果 SHBG、T和E2浓度在糖尿病组分别为(62.50±27.08)nmol/L、(48.41±9.96)nmol/L和(150.84±96.81)pmol/L,而在对照组分别为(74.16±32.30)nmol/L、(50.55±12.39)nmol/L和(166.03±121.55)pmol/L,三个指标两组间比较差异均无统计学意义(P＞0.05).糖尿病组组内相关因素分析发现,SHBG与年龄呈正相关(r=0.54,P＜0.01),与体重指数(BMI)呈负相关(r=-0.46,P＜0.01),并与空腹胰岛素呈负相关(r=-0.48,P＜0.01).逐步回归分析发现,年龄和BMI对SHBG影响最大.结论 2型糖尿病本身对SHBG和性激素浓度无明显影响,而年龄和BMI是其独立影响因素.     

商品与自制匀浆膳对卧床病人营养及生化状况影响的比较

目的:比较商品匀浆膳与传统自制匀浆膳对长期卧床病人营养状况及生化检测指标的影响.方法:选择住院病人39例,采用人群自身对照研究方法,对每一位病人分别进行传统自制匀浆及商品匀浆管饲喂养,时间均为6个月.每月对其进行一次人体测量,收集三头肌皮皱厚度(TSF)和上臂围(MAC)结果.每月检测两次血清总蛋白(TP)、血清清蛋白(ALB)、三酰甘油(TG)、血胆固醇(TC)和血肌酐(Cr)、血尿素氮(BUN)、血清总胆红素(STB)、直接胆红素(CB)、血钙(Ca)、血磷(P)、血钠(Na)、血钾(K)等.取各种指标结果的平均值,比较两种不同匀浆膳组各项指标的差异.结果:39例病人在观察期内服用自制或商品匀浆膳均未出现腹胀、腹泻、腹痛、恶心、呕吐等胃肠道反应.除血Na商品匀浆膳组低于自制匀浆膳组(P＜0.05)外,其余各项指标两组间差异均无显著性意义(P＞0.05).结论:配比合理的匀浆膳是老年卧床病人肠内营养支持的一种比较理想的制剂,自制与商品匀浆膳均具有独自的特点和优势,应同时存在,配合使用.     

双生子学龄儿童体格发育遗传学分析

目的 分析遗传与环境因素对学龄双生子儿童体格发育的影响,分析其中年龄和性别的作用.方法测量297对6～12岁(同卵167对,同性别异卵90对,异性别异卵40对)学龄儿童身高、坐高、体重、胸围、肱三头肌皮褶、肩胛下皮褶、髂前皮褶厚度;用Mx软件拟合最佳结构方程模型.结果各体格指标均与年龄相关,仅肱三头肌皮褶厚度与性别相关;各指标的遗传模型均为ACES,遗传方差组分高于环境方差组分,男性皮褶厚度的共同环境效应高于女性,皮褶厚度的年龄方差(0.02 ～0.17)明显低于其他指标(0.35 ～0.74);校正年龄后,遗传度分别为身高(男0.80,女0.83)、坐高(男0.76,女0.79)、体重(男0.53,女0.73)、胸围(男0.72,女0.66)、肱三头肌皮褶(男0.51,女0.87)、肩胛下皮褶(男0.56,女0.86)、髂前皮褶(男0.51,女0.83),女生体重及皮褶厚度的遗传度均明显高于男生.结论遗传因素对学龄儿童体格发育起主要作用,但年龄、性别对其也有一定影响.     

The effect of substituting alternative grains in the diet on the nutritional profile of the gluten-free diet

Background:  The only treatment for coeliac disease is lifelong adherence to a gluten-free diet. Several studies have reported nutritional deficiencies in individuals on a gluten-free diet. The present study aimed to determine whether the nutritional profile of gluten-free diet could be improved through the use of alternative grains.
Methods:  A retrospective review of diet history records by a celiac specialist dietitian were used to establish a 'standard' gluten-free dietary pattern. An 'alternative' gluten-free dietary pattern was developed that substituted naturally gluten-free grains or gluten-free products made from 'alternative' flours (oats, high fibre gluten-free bread and quinoa) in the standard pattern. A paired t- test was performed to identify statistical significance between the 'alternative' and standard gluten-free dietary pattern.
Results:  Analysis of standard pattern indicated that 38% of meals and snacks contained no grain or starch choice. Of those meals that contained a grain or starch component, rice was the grain chosen 44% of the time. The inclusion of alternative grains or grain products provided a higher nutrient profile compared to the standard gluten-free dietary pattern ( P  = 0.002). Several nutrients; protein (20.6 g versus 11 g), iron (18.4 mg versus 1.4 mg), calcium (182 mg versus 0 mg) and fibre (12.7 g versus 5 g) were significantly increased by changing the grain or starch component in the dietary pattern. The B vitamin content (riboflavin, niacin and folate) was improved, although this was not statistically significant ( P  = 0.125).
Discussion:  The inclusion of alternative grain-based products increased the nutrient profile of the gluten-free dietary pattern significantly.     

Iron deficiency: effect on plasma luteinizing hormone and testosterone levels in the adult male rat

We studied four groups of animals, all of which received an iron-deficient diet for 6 wk followed by a 4-wk recovery period during which all groups received Fe supplements. Group 1 (n = 12) and group 2 (n = 10) were intact male rats; group 1 received a dietary Fe supplement whereas group 2 received no Fe supplement. Group 3 (n = 12) and group 4 (n = 12) were castrated male rats; group 3 received a dietary Fe supplement whereas group 4 received no supplement. Analysis of circulating hormone values revealed that after 6 wk of dietary treatment, neither LH nor testosterone levels were affected by the Fe-deficient diet in either the castrated or intact groups. These observations suggest that neither testosterone secretion per se nor its feedback control by LH is affected by short-term Fe deficiency.