• 【自我选择对更快,更远的男性和女性步行者的肥胖程度有很大贡献。】 复制标题 收藏 收藏
    DOI:10.1038/sj.ijo.0803457 复制DOI
    作者列表:Williams PT
    BACKGROUND & AIMS: OBJECTIVE:Cross-sectional studies show that active individuals are leaner than their sedentary counterparts. The purpose of this paper is to determine the extent that this is due to self-selection bias, specifically to initially leaner men and women choosing to exercise longer and more intensely. METHODS:Walking quantity (weekly distance) and intensity (speed) were compared to current body mass index (BMI) (BMI(current)) and BMI at the start of walking (BMI(starting)) in 20,353 women and 5174 men who on average had walked regularly for exercise for 7.2 and 10.6 years, respectively. RESULTS:The relationships of both BMI(current) and BMI(starting) to both distance and intensity were nonlinear (convex). On average, BMI(starting) explained >70% of the association between BMI(current) and intensity, and 40 and 17% of the associations between BMI(current) and distance in women and men, respectively. Although the declines in BMI(current) with distance and intensity were greater among fatter individuals than leaner individuals, the portions attributable to BMI(starting) remained relatively constant regardless of fatness. Thus, self-selection bias accounted for most of the decline in BMI with walking intensity and smaller, albeit significant, proportions of the decline with distance. CONCLUSION:Although walking intensity and walking distance are both strongly associated with greater leanness, intensity is less likely to be causally related to leanness than is distance, and the latter should be encouraged for reversing or preventing weight gain.
    背景与目标:
  • 【男性乳腺癌ERBB2基因状态和17号染色体异常的评价。】 复制标题 收藏 收藏
    DOI:10.1097/01.pas.0000213354.72638.bd 复制DOI
    作者列表:Fonseca RR,Tomás AR,André S,Soares J
    BACKGROUND & AIMS: :Male breast cancer (MBC) is an uncommon neoplasm that shares several biologic characteristics with its female counterpart. In the latter, abnormalities in the expression and/or copy number of the ERBB2 gene are present in 10% to 30% of invasive carcinoma and behave as poor prognostic markers. ERBB2 abnormalities have also been reported in MBC, yet at lower frequency, but their prognostic significance remains controversial. Furthermore, no study has addressed the impact of chromosome 17 abnormalities in MBC survival. In this study, the ERBB2-gene status (overexpression and amplification) and chromosome 17 numerical abnormalities were investigated in a series of 50 archival cases of MBC. The results, together with patient's age, histologic grade, pathologic stage, and estrogen receptor status were correlated with overall survival. ERBB2-protein overexpression was present in 7 cases (14%), ERBB2-gene amplification in 4 (8%), and aneuploidy of chromosome 17 in 12 cases (33.3%). The pathologic stage, ERBB2 overexpression and ERBB2 amplification were significantly correlated with overall survival (P=0.002, 0.016, and 0.009, respectively). No correlation was observed between chromosome 17 aneuploidy and overall survival. Therefore, despite their low incidence in MBC, expression abnormalities of ERBB2 behave, together with the pathologic stage of the tumor, as predictors of overall survival, akin to what has been reported for its female counterpart.
    背景与目标: : 男性乳腺癌 (MBC) 是一种罕见的肿瘤,与女性具有多种生物学特征。在后者中,ERBB2基因的表达和/或拷贝数的异常存在于10% 浸润性癌的30% 中,并且表现为不良的预后标志物。在MBC中也有ERBB2异常的报道,但频率较低,但其预后意义仍存在争议。此外,还没有研究涉及17号染色体异常对MBC存活的影响。在这项研究中,在一系列50例MBC档案病例中研究了ERBB2-gene状态 (过表达和扩增) 和17号染色体数字异常。结果以及患者的年龄,组织学分级,病理分期和雌激素受体状态与总生存率相关。ERBB2-protein过表达7例 (14%),ERBB2-gene扩增4例 (8%),17号染色体非整倍性12例 (33.3%)。病理分期,ERBB2过表达和ERBB2扩增与总生存期显着相关 (分别为P = 0.002,0.016和0.009)。在17号染色体非整倍性与总生存率之间未观察到相关性。因此,尽管ERBB2在MBC中的发生率较低,但其表达异常与肿瘤的病理阶段一起表现为总体生存的预测指标,类似于已报道的女性对应物。
  • 【在一项对照横断面研究中,年轻男性癌症幸存者中雄激素缺乏的患病率和后果。】 复制标题 收藏 收藏
    DOI:10.1210/jc.2006-2744 复制DOI
    作者列表:Greenfield DM,Walters SJ,Coleman RE,Hancock BW,Eastell R,Davies HA,Snowden JA,Derogatis L,Shalet SM,Ross RJ
    BACKGROUND & AIMS: BACKGROUND:Testosterone replacement in hypogonadal males improves body composition, sexual function, and health-related quality of life. Male cancer survivors are at risk of androgen deficiency; however, when and in whom testosterone should be replaced remain unanswered questions. OBJECTIVE:The aim of our study was to define the prevalence of androgen deficiency in this patient group through assessment of testosterone levels and related measures. DESIGN:This was a cross-sectional, observational study of cases and controls. We recruited 176 cancer survivors and 213 controls, aged 25-45 yr. RESULTS:Of cancer survivors, 97% had received chemotherapy and 40% radiotherapy. Cancer survivors had lower total testosterone (tT) levels than controls (mean difference 2.67 nmol/liter; 95% confidence interval 1.58-3.76; P = 0.003), and 24 of 176 (13.6%; 95% confidence interval 9.3-19.5) had a tT less than 10 nmol/liter, which was less than 2.5% centile for controls. Cancer survivors had a greater fat mass, higher fasting insulin and glucose levels, increased fatigue, and reduced sexual function and health-related quality of life. In both cohorts, the tT correlated negatively with insulin levels and negatively with body fat mass; however, the difference in tT between them was independent of fat mass. We measured tT and SHBG and calculated bioavailable testosterone. The changes in calculated bioavailable testosterone were similar to tT. CONCLUSIONS:A significant proportion of young male cancer survivors had a frankly low tT associated with an increased fat mass and insulin level compared with controls. These factors would be predicted to improve in response to testosterone replacement therapy and provide a powerful argument for an interventional study of testosterone therapy in young male cancer survivors.
    背景与目标:
  • 【Y染色体平衡相互易位病例中男性不育的细胞遗传学和分子研究。】 复制标题 收藏 收藏
    DOI:10.3892/mmr.2017.6835 复制DOI
    作者列表:Wang D,Chen R,Kong S,Pan QY,Zheng YH,Qiu WJ,Fan Y,Sun XF
    BACKGROUND & AIMS: :Y-autosomal translocation has been previously reported in association with male infertility; however, the mechanisms of Y-autosomal translocation and non‑obstructive azoospermia or severe oligospermia remain unclear. G‑banding and fluorescence in situ hybridization (FISH) were performed to analyze the translocation of chromosomes, and a single nucleotide polymorphism (SNP) genotyping assay was used to test mutations. The present study describes three new cases with a de novo balanced translocation t(Y;13), t(Y;9) and t(Y;6). To further explore the genotype‑phenotype correlation, G‑banding and FISH were performed and indicated the presence of a derivative chromosome. The SNP genotyping assay using a microarray revealed no abnormality, especially in the Y chromosome. Molecular deletion analysis demonstrated that no microdeletion was detected in the azoospermia factor region of the Y chromosome in the examined, infertile men. Based on these observations, the authors proposed the hypothesis that a position effect involving unknown spermatogenesis regulatory gene(s) serves a key role in male infertility.
    背景与目标: : Y常染色体易位与男性不育有关。但是,Y常染色体易位和非阻塞性无精子症或严重少精子症的机制尚不清楚。进行g-带和荧光原位杂交 (FISH) 以分析染色体的易位,并使用单核苷酸多态性 (SNP) 基因分型分析来测试突变。本研究描述了三个从头平衡易位t(Y;13),t(Y;9) 和t(Y;6) 的新病例。为了进一步探索基因型表型的相关性,进行了g-带和FISH,并指出存在衍生染色体。使用微阵列的SNP基因分型分析未显示异常,尤其是在Y染色体中。分子缺失分析表明,在被检查的不育男性中,在Y染色体的无精子因子区域中未检测到微缺失。基于这些观察结果,作者提出了以下假设: 涉及未知精子发生调节基因的位置效应在男性不育中起关键作用。
  • 【[随访5年以上男性尿道狭窄治疗结果评价]。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Khenifar E,Guerder L,Jeldi A,Bittard H
    BACKGROUND & AIMS: :149 cases of urethral stricture were treated in the Urology Department from 1971 to 1984. All of these patients have therefore been treated with a minimal follow-up of 5 years. There were 87 cases of post-traumatic stricture, 53 of whom were lost to follow-up during the survey, 8 died and 26 patients were able to be reviewed. The remaining 62 cases consisted of post-infectious strictures, with 37 patients lost to follow-up during the survey, 1 patient who died and 24 patients who were reviewed. The patients reviewed were assessed according to the criteria of the SFU (French Urology Society) survey. Direct vision internal urethrotomy was performed in 33 cases with 18 very good or good results (54%), segmental resection was performed in 10 cases with 7 very good or good results, urethroplasty was performed in 4 cases with 2 good results and 2 urethral dilatations were performed with 2 good results. The failures were essentially treated by more complex surgery (urethroplasty).
    背景与目标: : 泌尿科1971年1984年治疗尿道狭窄149例。因此,所有这些患者均接受了5年的最小随访。外伤性狭窄87例,其中53例在调查中失访,8例死亡,26例患者得以复查。其余62例为感染后狭窄,其中37例患者在调查中失访,1例死亡,24例患者接受复查。根据SFU (法国泌尿外科学会) 调查的标准对患者进行评估。33例行直视内尿道切开术,18例效果非常好或良好 (54%),10例行节段切除术,7例效果非常好或良好,4例行尿道成形术,2例尿道扩张,2例效果良好。这些失败基本上是通过更复杂的手术 (尿道成形术) 治疗的。
  • 【咖啡和咖啡因摄入量与男性不育: 系统评价。】 复制标题 收藏 收藏
    DOI:10.1186/s12937-017-0257-2 复制DOI
    作者列表:Ricci E,Viganò P,Cipriani S,Somigliana E,Chiaffarino F,Bulfoni A,Parazzini F
    BACKGROUND & AIMS: BACKGROUND:Semen quality, a predictor of male fertility, has been suggested declining worldwide. Among other life style factors, male coffee/caffeine consumption was hypothesized to influence semen parameters, but also sperm DNA integrity. To summarize available evidence, we performed a systematic review of observational studies on the relation between coffee/caffeine intake and parameters of male fertility including sperm ploidy, sperm DNA integrity, semen quality and time to pregnancy. METHODS:A systematic literature search was performed up to November 2016 (MEDLINE and EMBASE). We included all observational papers that reported the relation between male coffee/caffeine intake and reproductive outcomes: 1. semen parameters, 2. sperm DNA characteristics, 3. fecundability. All pertinent reports were retrieved and the relative reference lists were systematically searched in order to identify any potential additional studies that could be included. RESULTS:We retrieved 28 papers reporting observational information on coffee/caffeine intake and reproductive outcomes. Overall, they included 19,967 men. 1. Semen parameters did not seem affected by caffeine intake, at least caffeine from coffee, tea and cocoa drinks, in most studies. Conversely, other contributions suggested a negative effect of cola-containing beverages and caffeine-containing soft drinks on semen volume, count and concentration. 2. As regards sperm DNA defects, caffeine intake seemed associated with aneuploidy and DNA breaks, but not with other markers of DNA damage. 3. Finally, male coffee drinking was associated to prolonged time to pregnancy in some, but not all, studies. CONCLUSIONS:The literature suggests that caffeine intake, possibly through sperm DNA damage, may negatively affect male reproductive function. Evidence from epidemiological studies on semen parameters and fertility is however inconsistent and inconclusive. Well-designed studies with predefined criteria for semen analysis, subject selection, and life style habits definition, are essential to reach a consistent evidence on the effect of caffeine on semen parameters and male fertility.
    背景与目标:
  • 【雌性普通鱼  ×  型雄性钝吻鲷种间杂交衍生的一种新型同二倍体鱼类。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-017-04582-z 复制DOI
    作者列表:Wang S,Ye X,Wang Y,Chen Y,Lin B,Yi Z,Mao Z,Hu F,Zhao R,Wang J,Zhou R,Ren L,Yao Z,Tao M,Zhang C,Xiao J,Qin Q,Liu S
    BACKGROUND & AIMS: :It is commonly believed that hybridization might lead to the formation of new polyploidy species, but it is unclear whether hybridization can produce a new homodiploid species. Here, we report the spontaneous occurrence of a new crucian carp-like homodiploid fish (2n = 100) that originated from the interspecific hybridization of female common carp (Cyprinus carpio, Cyprininae, 2n = 100) × male blunt snout bream (Megalobrama amblycephala, Cultrinae, 2n = 48). The phenotype and reproductive traits of this new crucian carp-like homodiploid fish were found to be very similar to those of the existing diploid species (diploid crucian carp; Carassius auratus). FISH and 5S rDNA analyses revealed that the genotype of the crucian carp-like homodiploid fish differs from those of its parents but is closely related to that of diploid crucian carp. The results provide evidence of the existence of a possible route through which the distant hybridization of this cross can generate crucian carp. The new type of homodiploid fish is of great value in fish genetic breeding and for studying the early evolutionary process.
    背景与目标: : 通常认为杂交可能导致形成新的多倍体物种,但目前尚不清楚杂交是否可以产生新的同二倍体物种。在这里,我们报道了一种新的鲫鱼样同二倍体鱼 (2n   =   100) 的自发发生,该鱼起源于雌性鲤鱼的种间杂交 (Cyprinus carpio,cyprinininae,2n   =   100) ×  雄性钝吻鲷 (Megalobrama amblycephala,Cultrinae,2n   =   48)。发现这种新的cru鱼状同二倍体鱼类的表型和繁殖性状与现有的二倍体物种 (二倍体cru鱼; Car鱼) 非常相似。FISH和5S rDNA分析表明,cru鱼样同二倍体鱼的基因型与其亲本不同,但与二倍体cru鱼的基因型密切相关。结果提供了证据,表明存在一种可能的途径,通过该途径,该杂交的远距离杂交可以产生cru鱼。新型同二倍体鱼类在鱼类遗传育种和早期进化过程研究中具有重要价值。
  • 【雄性和雌性大鼠在青春期前后进行性腺切除术后,对乙醇引起的条件性味觉厌恶的敏感性出现差异。】 复制标题 收藏 收藏
    DOI:10.1016/j.bbr.2012.11.020 复制DOI
    作者列表:Morales M,Spear LP
    BACKGROUND & AIMS: :We have previously demonstrated that gonadectomy either prior to (early) or after (late) puberty elevated ethanol consumption in males to levels similar to intact adult females-effects that were attenuated by testosterone replacement. To assess whether alterations in the aversive effects of ethanol might contribute to gonadectomy-associated increases in ethanol intake in males, the present study examined the impact of gonadectomy on conditioned taste aversions (CTA) to ethanol in male and female Sprague-Dawley rats. Animals were gonadectomized, received sham surgery (SH) or non-manipulated (NM) on postnatal (P) day 23 (early) or 67 (late) and tested for CTA to ethanol in adulthood. Water-deprived rats were given 1 hr access every-other-day to 10% sucrose followed by an injection of ethanol (0, 1g/kg) for 5 test sessions. Test data were analyzed to determine the first day significant aversions emerged in each ethanol group (i.e., sucrose intakes significantly less than their saline-injected counterparts). Early gonadectomized males acquired the CTA more rapidly than did early SH and NM males (day 1 vs 3 and 4 respectively), whereas a gonadectomy-associated enhancement in ethanol CTA was not evident in late males. Among females, gonadectomy had little impact on ethanol-induced CTA, with females in all groups showing an aversion by the first or second day, regardless of surgery age. These data suggest that previously observed elevations in ethanol intake induced by either pre- or post-pubertal gonadectomy in males are not related simply to gonadectomy-induced alterations in the aversive effects of ethanol indexed via CTA.
    背景与目标: : 我们以前已经证明,在青春期 (早期) 或青春期 (晚期) 之前进行性腺切除术会将男性的乙醇消耗量提高到与完整的成年女性相似的水平-睾丸激素替代作用会减弱。为了评估乙醇的厌恶作用的改变是否可能导致男性性腺切除术相关的乙醇摄入量增加,本研究检查了性腺切除术对雄性和雌性Sprague-Dawley大鼠对乙醇的条件性味厌恶 (CTA) 的影响。在出生后第23天 (早期) 或第67天 (晚期) 对动物进行性腺切除,接受假手术 (SH) 或非操纵 (NM),并在成年后测试CTA至乙醇。每隔一天给缺水的大鼠1小时10% 蔗糖,然后注射乙醇 (0,1 g/kg) 进行5次测试。分析测试数据以确定每个乙醇组中出现的第一天明显厌恶 (即,蔗糖摄入量明显少于注射盐水的对应物)。早期性腺切除的男性获得CTA的速度比早期SH和NM的男性更快 (分别为第1天和第3天和第4天),而在晚期男性中,性腺切除术相关的乙醇CTA增强并不明显。在女性中,性腺切除术对乙醇诱导的CTA几乎没有影响,无论手术年龄如何,所有组的女性在第一天或第二天都表现出厌恶情绪。这些数据表明,先前观察到的男性青春期前或青春期后性腺切除术引起的乙醇摄入量升高与性腺切除术引起的通过CTA索引的乙醇厌恶作用的改变无关。
  • 【产前暴露于抗真菌药物可能会改变雄性后代的肛门生殖距离: 一项初步研究。】 复制标题 收藏 收藏
    DOI:10.1186/s12940-017-0263-z 复制DOI
    作者列表:Mogensen DM,Pihl MB,Skakkebæk NE,Andersen HR,Juul A,Kyhl HB,Swan S,Kristensen DM,Andersen MS,Lind DV,Jensen TK
    BACKGROUND & AIMS: BACKGROUND:Vaginal candidiasis is frequent among pregnant women and it is treated with anti-fungal medication (conazoles). Conazoles have anti-androgenic properties and prenatal exposure in rodents is associated with a shorter (less masculine) anogenital distance (AGD) in male offspring. To our knowledge this has never been studied in humans. METHOD:In the Odense Child Cohort pregnant women residing in Odense municipality, Denmark, were recruited at gestational age 8-16 weeks between 2010 and 2012. Of the eligible 2421 mother-child pairs, 812 mother-son pairs were included. Questionnaire data on medicine use were collected in first and third trimester and physical examination at age 3 month was performed. Ano-scrotal distance; measured from the centre of anus to the posterior base of scrotum (AGDas). Ano-cephalad distance; measured from the centre of anus to the cephalad insertion of the penis (AGDap) and penile width; measured at the base of the penis. RESULTS:Eighty seven women had used antifungal medicine during pregnancy. Maternal use of oral fluconazole (n = 4) was associated with a 6.4 mm shorter AGDas (95% CI: -11.9;-0.9) in the male offspring. Use of antifungal vaginal tablets (n = 21), was associated with a non-significantly shorter AGDas (-1.9 mm; 95% CI: -4.3; 0.5) whereas exposure to vaginal cream (n = 23) was not associated to AGDas. Use of antifungal medicine in the window of genital development between 8 and 14 weeks of gestation was associated with a larger reduction in AGDas than exposure outside this window. Antifungal medicine intake was not associated with AGDap and penil width. CONCLUSION:Our preliminary findings prompted us to hypothesize that maternal use of conazole antifungal medication during pregnancy may affect the masculinization of male offspring. If confirmed, pregnant women should be advised to use antifungal medicine with caution.
    背景与目标:
  • 【预先接触吗啡对大麻素诱导的雄性大鼠空间记忆损伤的影响。】 复制标题 收藏 收藏
    DOI:10.1016/j.bbr.2013.07.054 复制DOI
    作者列表:Farahmandfar M,Kadivar M,Naghdi N,Choopani S,Zarrindast MR
    BACKGROUND & AIMS: :In the present study, we investigated the effects of repeated morphine pre-treatment on impairment of spatial memory acquisition induced by intra dorsal hippocampus (intra-CA1) administration of the non-selective cannabinoid CB1/CB2 receptor agonist, WIN55,212-2 in adult male rats. 2-day version of Morris water maze task has been used for the assessment of spatial memory. On the training day, rats were trained by a single training session of eight trials and 24 h later a probe trial test consist of 60s free swim period without a platform and the visible test was administered. Animals received pre-treatment subcutaneous (s.c.) injections of morphine, once daily for three days followed by five days drug-free treatment before training trials. The results indicated that bilateral pre-training intra-CA1 infusions of WIN55,212-2 (0.25 and 0.5 μg/rat) impaired acquisition of spatial memory on the training and test day. The amnesic effect of WIN55, 212-2 (0.5 μg/rat) was prevented in rats previously injected with morphine (20 mg/kg/day × 3 days, s.c.). Improvement in spatial memory acquisition in morphine-pretreated rats was inhibited by once daily administration of naloxone (1 and 2 mg/kg, s.c.) 15 min prior to injection of morphine for three days. The results suggest that sub-chronic morphine treatment may produced sensitization to cannabinoids, which in turn reversed the impairment of spatial memory acquisition induced by WIN55,212-2 and mu- opioid receptors may play an important role in this effect.
    背景与目标: : 在本研究中,我们研究了重复吗啡预处理对非选择性大麻素CB1/CB2受体激动剂WIN55、212-2在成年雄性大鼠中给予背海马 (intra-CA1) 引起的空间记忆获取障碍的影响。莫里斯水迷宫任务的2天版本已用于评估空间记忆。在训练当天,对大鼠进行了八次试验的单次训练,24小时后进行了一次探针试验测试,该试验包括60s的自由游泳期,没有平台,并进行了可见测试。动物接受治疗前皮下注射吗啡,每天一次,持续三天,然后在训练试验前进行五天的无药治疗。结果表明,在训练和测试当天,双侧训练前intra-CA1输注WIN55,212-2 (0.25和0.5 μ g/大鼠) 会损害空间记忆的获取。在先前注射吗啡 (20 mg/kg/天 × 3天,s.C.) 的大鼠中预防WIN55,212-2 (0.5 μ g/大鼠) 的遗忘作用。每天服用一次纳洛酮 (1和2 mg/kg,s.C.) 可抑制吗啡预处理大鼠空间记忆的获取。注射吗啡前15分钟,持续三天。结果表明,亚慢性吗啡治疗可能会产生对大麻素的敏感性,从而逆转由WIN55,212-2和mu-阿片受体引起的空间记忆获取障碍可能在这种作用中起重要作用。
  • 【男性危险行为的代价: 小型单态灵长类动物季节性生存的性别差异。】 复制标题 收藏 收藏
    DOI:10.1098/rspb.2008.0200 复制DOI
    作者列表:Kraus C,Eberle M,Kappeler PM
    BACKGROUND & AIMS: :Male excess mortality is widespread among mammals and frequently interpreted as a cost of sexually selected traits that enhance male reproductive success. Sex differences in the propensity to engage in risky behaviours are often invoked to explain the sex gap in survival. Here, we aim to isolate and quantify the survival consequences of two potentially risky male behavioural strategies in a small sexually monomorphic primate, the grey mouse lemur Microcebus murinus: (i) most females hibernate during a large part of the austral winter, whereas most males remain active and (ii) during the brief annual mating season males roam widely in search of receptive females. Using a 10-year capture-mark-recapture dataset from a population of M. murinus in Kirindy Forest, western Madagascar, we statistically modelled sex-specific seasonal survival probabilities. Surprisingly, we did not find any evidence for direct survival benefits of hibernation-winter survival did not differ between males and females. By contrast, during the breeding season males survived less well than females (sex gap: 16%). Consistent with the 'risky male behaviour' hypothesis, the period for lowered male survival was restricted to the short mating season. Thus, sex differences in survival in a promiscuous mammal can be substantial even in the absence of sexual dimorphism.
    背景与目标: : 男性过度死亡率在哺乳动物中普遍存在,通常被解释为性选择性状的成本,这些性状可以提高男性的生殖成功。经常援引从事危险行为的倾向中的性别差异来解释生存中的性别差距。在这里,我们的目的是分离和量化两种潜在风险的男性行为策略在一个小的性单形灵长类动物,灰鼠狐猴Microcebus murinus的生存后果 :( i) 大多数雌性在大部分冬季冬眠,尽管大多数雄性保持活跃,并且 (ii) 在短暂的年度交配季节,雄性广泛漫游以寻找接受雌性。使用来自马达加斯加西部Kirindy森林的M. murinus种群的10年捕获-标记-捕获数据集,我们对特定性别的季节性生存概率进行了统计建模。令人惊讶的是,我们没有发现任何证据表明冬眠的直接生存益处-冬季生存在男性和女性之间没有差异。相比之下,在繁殖季节,雄性的存活不如雌性 (性别差距: 16%)。与 “危险的男性行为” 假设一致,降低男性存活率的时间仅限于短暂的交配季节。因此,即使没有性别二态性,混杂哺乳动物的生存性别差异也可能很大。
  • 【自由生活的雄性西方钻石背响尾蛇Crotalus atrox (蛇形: 毒蛇科) 中血浆性类固醇水平的冬季概况。】 复制标题 收藏 收藏
    DOI:10.1016/j.ygcen.2006.05.005 复制DOI
    作者列表:Schuett GW,Repp RA,Taylor EN,DeNardo DF,Earley RL,Van Kirk EA,Murdoch WJ
    BACKGROUND & AIMS: :Recent field studies on the reproductive ecology of western diamond-backed rattlesnakes (Crotalus atrox) from populations in southern Arizona showed significant differences in the concentration of plasma sex steroids (testosterone, T; 5alpha-dihydrotestosterone, DHT; and 17beta-estradiol, E2) throughout the active season (March-October), and peak levels were coincident with the two mating periods (late summer and early spring). There is, however, no information on levels of sex steroids during winter. Similar to most snakes, hibernating individuals of C. atrox are typically inaccessible, but in southern Arizona, where environmental conditions are typically mild during winter, adult males frequently bask at or near the entrances of communal dens. Basking activity, therefore, offers a unique logistical opportunity to assess the complete annual profile of plasma sex steroid levels in males of a temperate reptile in nature. From November to February, we measured levels of plasma T, DHT, and E2 in adult male C. atrox that were located basking at communal dens. Additionally, cloacal, core body, and ambient air temperatures were obtained to investigate potential relationships between body temperatures and levels of sex steroids. Mean levels of T, DHT, and E2 were relatively high, and the concentration hierarchy was T>DHT>E2. Mean levels of T, DHT, and E2 showed no significant variation across the four months of sampling; however, E2 levels decreased progressively. In the annul cycle, sex steroid levels during winter were not basal when compared to values obtained during the active season. Mean cloacal temperatures of basking males were significantly higher than core body temperatures of non-basking males (inside dens) from November-December, and in February, which suggests that one function of winter basking is to elevate body temperatures. Steroid levels, nonetheless, were not significantly correlated with cloacal temperatures. We suggest that future field studies of male C. atrox should: (a) investigate sex steroid levels in non-basking individuals and (b) test whether elevated levels of sex steroids during winter facilitate the large increases that occur in early spring, which are coincident with the second mating season. Our findings on the reproductive biology of C. atrox and other viperids are discussed in the context of the associated-dissociated model of reproduction.
    背景与目标: : 最近对来自亚利桑那州南部种群的西方钻石支持响尾蛇 (Crotalus atrox) 的生殖生态学进行的实地研究表明,血浆性类固醇 (睾丸激素,T; 5α-二氢睾丸激素,DHT; 和17β-雌二醇,E2) 在整个活动季节 (3月-10月),峰值水平与两个交配期 (夏末和初春) 一致。但是,没有关于冬季性类固醇水平的信息。与大多数蛇相似,通常无法进入冬眠的C. atrox个体,但在亚利桑那州南部,冬季环境条件通常温和,成年雄性经常在公共窝点的入口或附近晒太阳。因此,晒太阳活动提供了一个独特的后勤机会,可以评估自然界中温带爬行动物男性的血浆性类固醇水平的完整年度概况。从11月到2月,我们测量了位于公共窝点的成年男性C. atrox的血浆T,DHT和E2水平。此外,还获得了泄殖腔,核心体和环境空气温度,以研究体温与性类固醇水平之间的潜在关系。T,DHT和E2的平均水平相对较高,浓度等级为T>DHT>E2。在四个月的采样中,T,DHT和E2的平均水平没有显着变化; 但是,E2水平逐渐降低。在annul周期中,与活动季节获得的值相比,冬季的性类固醇水平不是基础。在11月12月和2月中,晒太阳的男性的平均泄殖腔温度显着高于非晒太阳的男性 (窝点内) 的核心体温,这表明冬季晒太阳的功能之一是提高体温。尽管如此,类固醇水平与泄殖腔温度没有显着相关。我们建议将来对雄性C. atrox进行实地研究 :( a) 调查非晒太阳个体的性类固醇水平,以及 (b) 测试冬季性类固醇水平升高是否会促进早春发生的大幅增加,这与第二个交配季节同时发生。我们在相关分离的生殖模型的背景下讨论了我们对C. atrox和其他生物的生殖生物学的发现。
  • 【日粮蛋白质和维生素水平对生长中的雄性大鼠在每日节律紊乱下性腺发育抑制的交互作用。】 复制标题 收藏 收藏
    DOI:10.3177/jnsv.53.138 复制DOI
    作者列表:Hanai M,Esashi T
    BACKGROUND & AIMS: :The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. The present study examined protein and vitamins, and their interactions. This study was based on three-way ANOVA; the three factors were lighting conditions, dietary protein and dietary vitamins, respectively. The levels of dietary protein were low or normal: 9% casein or 20% casein. The levels of dietary vitamins were low, normal or high: 1/3.3 of normal (AIN-93G diet) content, normal content, or three times the normal content, respectively. Other compositions were the same as those of the AIN-93G diet, and six kinds of experimental diet were prepared. Four-week-old rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. After 4 wk, the gonadal weights and serum testosterone content were evaluated. In the constant darkness groups (D-groups), the low-protein diet induced reduction of gonadal organ weights and serum testosterone concentrations. This reduction of gonadal organ weights was exacerbated by progressively higher levels of dietary vitamins. In the case of a normal-protein diet, the depression of gonadal development was not accelerated by high-vitamin intake. In the normal lighting groups (N-groups), the low-protein and high-vitamin diet slightly depressed gonadal development. These results suggest that the metabolism of protein and vitamins is different in rats being kept under constant darkness, and that excess dietary vitamins have an adverse effect on gonadal development in rats fed a low-protein diet.
    背景与目标: : 这项研究的目的是阐明营养物质对持续处于黑暗状态下的雄性大鼠性腺发育的影响,以此作为每日节律紊乱的模型。本研究检查了蛋白质和维生素及其相互作用。本研究基于三次方差分析; 这三个因素分别是光照条件、膳食蛋白质和膳食维生素。膳食蛋白质水平低或正常: 9% 酪蛋白或20% 酪蛋白。饮食中的维生素水平低,正常或高: 正常 (AIN-93G饮食) 含量的1/3.3,正常含量或正常含量的3倍。其他组成与AIN-93G饮食相同,并准备了六种实验饮食。将4周龄的大鼠 (Fischer 344品系) 保持在恒定的黑暗或正常照明下 (12小时的光/暗周期) 4周。4周后,评估性腺重量和血清睾丸激素含量。在恒定的黑暗组 (D组) 中,低蛋白饮食导致性腺器官重量和血清睾丸激素浓度降低。饮食中维生素的含量逐渐增加,加剧了性腺器官重量的减少。在正常蛋白质饮食的情况下,高维生素摄入量不会加速性腺发育的抑制。在正常照明组 (N组) 中,低蛋白和高维生素饮食会稍微抑制性腺发育。这些结果表明,在持续黑暗的情况下,大鼠的蛋白质和维生素的代谢是不同的,并且过量的饮食维生素对喂养低蛋白饮食的大鼠的性腺发育有不利影响。
  • 【体重指数,腰围和腰臀比以及性类固醇激素的变化: 马萨诸塞州男性衰老研究。】 复制标题 收藏 收藏
    DOI:10.1111/j.1365-2265.2006.02560.x 复制DOI
    作者列表:Derby CA,Zilber S,Brambilla D,Morales KH,McKinlay JB
    BACKGROUND & AIMS: OBJECTIVE:Cross-sectional data suggest that obesity, particularly central obesity, may be associated with decreased production of sex steroid hormones in men. However, longitudinal hormone data on men in relation to obesity status are limited. Previous studies have not consistently demonstrated whether sex steroids are associated specifically to body mass index or to measures of central obesity. Our objective was to examine the relation of obesity (body mass index > 30 kg/m2), and of central obesity (waist circumference > 100 cm or waist to hip ratio > 0.95) to longitudinal change in sex steroid hormones in men. DESIGN:Prospective follow-up of a population-based sample of men in Boston. PATIENTS:Nine hundred forty-two (942) men in the Massachusetts Male Ageing Study with complete anthropometry and hormone data at baseline (1987-1989, ages 40-70) and follow-up (1995-1997). MEASUREMENTS:Free and total testosterone (FT and TT), dehydroepiandrosterone sulphate (DHEAS), and sex hormone-binding globulin (SHBG) were assessed using standardized methods. Health behaviours and medical history were obtained by structured interview. Repeated measures regression was used to describe trends in steroid hormones and SHBG in relation to obesity status, adjusting for age, smoking, alcohol, comorbidities, and physical activity. RESULTS:Obesity was associated with decreased levels of total and free testosterone, and of SHBG at follow-up relative to baseline. For any given baseline concentration of TT, FT or SHBG, follow-up levels were lowest among men who remained obese or who became obese during follow-up. This was true for all three indices of obesity. Central adiposity was associated with lower DHEAS levels at follow-up, while elevated body mass index was not. CONCLUSIONS:Obesity may predict greater decline in testosterone and SHBG levels with age. Central adiposity may be a more important predictor of decline in DHEAS than is body mass index.
    背景与目标:
  • 【白蛋白藻酸盐包被的微球: 抗蒸汽灭菌和冻干。】 复制标题 收藏 收藏
    DOI:10.1016/j.ijpharm.2007.05.053 复制DOI
    作者列表:Callewaert M,Laurent-Maquin D,Edwards-Lévy F
    BACKGROUND & AIMS: :The paper describes the effect of different thermal treatments on the morphology and binding properties of particles prepared using a transacylation reaction between two biocompatible polymers, namely propylene glycol alginate and human serum albumin. Compared to control alginate gel microspheres, albumin-alginate covalent network offers a better resistance to the microspheres towards freezing, lyophilization and sterilization. The binding properties for methylene blue were not altered by the treatments. Moreover, stability in physiological environments opens interesting applications in biological and pharmaceutical fields.
    背景与目标: : 本文描述了不同热处理对使用两种生物相容性聚合物 (海藻酸丙二醇和人血清白蛋白) 之间的烷基转移反应制备的颗粒的形态和结合性能的影响。与对照藻酸盐凝胶微球相比,白蛋白-藻酸盐共价网络对微球的冷冻,冻干和灭菌具有更好的抵抗力。处理不会改变亚甲基蓝的结合特性。此外,生理环境中的稳定性在生物和制药领域开启了有趣的应用。

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