Vanadium transport across placenta and milk of rats to the fetus and newborn

The transport of vanadium across placenta and milk rats was studied by iv injection of low doses of 48V-labeled pentavanadate (0.1 micrograms V/rat) to pregnant and nursing rats. Significant concentrations of vanadium were found in the liver, intestine, and kidneys of the fetuses, showing that vanadium is capable to pass the placental barrier and, thus, being metabolized in the fetuses. Two days after injection of 0.1 micrograms V/rat as 48V-labeled vanadate to nursing rats, 34 ng V/g milk were found, decreasing to 4 ng V/g at the d 12 after dosing. The corresponding suckling rats showed a significant absorption of vanadium taken up by the milk, as suggested by the presence in their intestine, where 48V is easily absorbed in form of low molecular weight components. Vanadium in milk may be transported in the form of a biocomplex with lactoferrin, since at 12 d after injection, the 48V in the rat milk was mainly found in fractions corresponding to proteins. In weanling rats, 7 d postlactation and 18 d after administration of vanadium to the mother, only very small amounts of 48V were still present in the organs. Excretion studies on weanling rats for 7 d showed that vanadium is rapidly released mainly via feces when earlier taken up by the milk of iv injected mothers and having the same elimination pattern as the milk, which lost about 80% of its vanadium concentration after 12 d.     

Growth hormone responses to continuous and intermittent exercise in females under oral contraceptive therapy

In this study we investigated the effect of oral contraceptive (OC) use (OCU) and non-use (OCNU) on growth hormone (GH) responses to exercise in the same females (n = 7, age 22-31 years) during the normal course of OC therapy. Continuous (60% maximum oxygen consumption, VO2max for 20 min) and intermittent exercise (>80% VO2max) protocols of equal total duration, and similar external work were performed during phases of OCNU (days 3-5 of the menstrual cycle) and OCU (days 7-11). Levels of GH, lactate, 17 beta-estradiol, and progesterone were measured. Lactate responses were significantly greater (P<0.05) during intermittent than continuous exercise, with no effect of OC use. However, significantly greater GH responses were found during the OCU phase than the OCNU phase in both the continuous (+94%) and intermittent (+250%) exercise protocols. Estradiol and progesterone levels increased significantly during exercise in all four conditions. We suggest that the increased GH responses observed during the OCU-phase were potentiated by the elevated levels levels of total estrogens (endogenous 17 beta-estradiol and exogenous ethinyl estradiol). It is suggested that training programs for female athletes could be timed in accordance with the menstrual cycle to benefit from an increased GH response to exercise during phases of OC use or the luteal phase of women not on OC therapy.     

The influence of cold stress and a 36- h fast on the physiological responses to prolonged intermittent walking in man

In a previous study, rectal temperature (T _re) was found to be lower, and oxygen consumption (V˙O₂) and the respiratory exchange ratio (R) were higher in a cold (+5°C), wet and windy environment (COLD), compared with a thermoneutral environment during intermittent walking at ≈30% of peak V˙O₂ (Weller AS, Millard CE, Stroud MA et al. Am J Physiol 272:R226–R233, 1997). The aim of the present study was to establish whether these cold-induced responses are influenced by prior fasting, as impaired thermoregulation has been demonstrated in cold-exposed, resting men following a 48-h fast. To address this question, eight men attempted a 360-min intermittent (15 min rest, 45 min exercise) walking protocol under COLD conditions on two occasions. In one condition, the subjects started the exercise protocol ≈120 min after a standard meal (FED/COLD), whereas in the other the subjects had fasted for 36 h (FASTED/COLD). The first two exercise periods were conducted at a higher intensity (HIGHER, 6 km · h⁻¹ and 10% incline), than the four subsequent exercise periods (LOW, 5 km · h⁻¹ and 0% incline). There was no difference in the time endured in FED/COLD and FASTED/COLD. In FASTED/COLD com pared with FED/COLD, R was lower during HIGHER and LOW, and T _re was lower during LOW, whereas there was no difference in V˙O₂, mean skin temperature and heart rate. Therefore, although the 36-h fast impaired temperature regulation during intermittent low-intensity exercise in the cold, wet and windy environment, it was unlikely to have been the principal factor limiting exercise performance under these experimental conditions. Accepted: 26 August 1997     

Comparisons of serum testosterone and corticosterone between exercise training during normoxia and hypobaric hypoxia in rats

The purpose of this study was to compare the effects of continuous and intermittent exercise training on serum testosterone [T] and corticosterone concentrations [Cort] during normoxia and hypobaric hypoxia. Male rats swam with loads of 3% (normoxia) or 2.25% (462 mmHg) body mass for 60 min in the continuous training groups, and 15 min separated by a 7-min rest  × 4, with 60-min total exercise duration in the intermittent training groups, 5␣days · week⁻¹ for 6 weeks. Serum [T] were measured at␣rest and following exercise after 6 weeks of training. Serum [Cort] were measured immediately after an acute period of exercise or after 6 weeks of training at rest and following exercise. Continuous exercise induced decreases in [T] under both conditions. Intermittent exercise showed a tendency to increase [T] during normoxia, but caused a suppression during hypobaric hypoxia. The [Cort] was elevated by a similar margin after an acute period of exercise during both conditions. After 6 weeks of training, however, [Cort] increased slightly after exercise during normoxia. A lower resting [Cort], which was increased after exercise, was found in the training groups during hypoxia. No relevant relationship was found between the behaviours of [T] and [Cort] after exercise during either conditions. Accepted: 20 April 1998     

Rapid establishment of teat order and allonursing in wild boar (Sus scrofa)

Transfer of milk is the fundamental common characteristic of mammalian reproduction, but species differ considerably with respect to nursing strategies. The consequences of teat orders and allonursing have been studied intensively in domestic pigs. However, whether similar nursing strategies also exist in wild boar, the ancestor of domestic pigs is so far not known. The occurrence of allonursing in wild boar is only described anecdotally, and the question whether a teat order is established has not yet been investigated. Studying suckling behaviour of 29 piglets from six primiparous wild boar females in a semi‐natural environment we found a surprisingly fast development of a rigid teat order among littermates, which established within 2.2 hr after birth. This suggests strong fitness benefits of this phenomenon that may ultimately explain the evolution and maintenance of this trait. We further found a strong synchrony of oestrus and delivery among the females of a group, as well as the occurrence of allonursing. By determining the amount of allonursing for the first time quantitatively, we demonstrate the importance of this trait and its presumably pivotal role for juvenile survival under truly natural conditions.     

低频电刺激联合间歇导尿及Motomed运动训练对脊髓损伤致神经源性膀胱患者膀胱内压力及膀胱容量的影响

目的:探讨低频电刺激联合间歇导尿及Motomed运动训练对脊髓损伤致神经源性膀胱患者膀胱内压力及膀胱容量的影响。方法:选取我院2015年12月～2018年2月收治的脊髓损伤致神经源性膀胱患者92例,根据随机数字表法将其分为对照组(n=46)与研究组(n=46)。两组均给予间歇性导尿、盆底肌训练、膀胱功能训练等常规干预,对照组在此基础上采取低频电刺激,研究组于对照组基础上采取Motomed运动训练,两组均干预2个月。比较两组的临床疗效、治疗前及治疗2个月后的排尿情况(日均单次排尿量、日单次最大排尿量、日均排尿次数)、尿动力学情况(最大尿流率、膀胱容量、残余尿量、膀胱内压力)、LUTS(国际下尿路症状评分)及USDS(泌尿症状困扰评分)。结果:治疗后,研究组总有效率(93.48%)显著高于对照组(78.26%)(P0.05);治疗2个月后,两组日均单次排尿量、日单次最大排尿量、日均排尿次数、最大尿流率、膀胱容量、膀胱内压力均较治疗前显著增多,且研究组以上指标均明显高于对照组(P0.05);两组LUTS及USDS分值均较治疗前显著降低,且研究组以上指标均显著低于对照组(P0.05)。结论:间歇导尿联合低频电刺激与Motomed运动训练可有效改善脊髓损伤致神经源性膀胱患者尿动力学状态及排尿情况,增大膀胱容量及膀胱内压力等,缓解下尿路症状及泌尿症状困扰程度,提高治疗效果。     

黄芪注射液对网腔钙结合蛋白基因沉默阿霉素损伤心肌细胞内质网应激伴侣蛋白GRP78,GRP94 mRNA的作用

目的：研究黄芪注射液对网腔钙结合蛋白（calumenin）基因沉默阿霉素损伤心肌细胞内质网应激伴侣蛋白GRP78,GRP94 mRNA的作用。方法：实验将体外培养的1~3 d乳鼠心肌细胞分为5组：对照组、模型组（正常细胞+3 mg/L阿霉素）、calumenin基因沉默模型组（慢病毒感染细胞+3 mg/L阿霉素）、黄芪组1（正常细胞+3 mg/L阿霉素+200 g/L黄芪）、黄芪组2（慢病毒感染细胞+3 mg/L阿霉素+200 g/L黄芪）。构建慢病毒-calumenin质粒,转染乳鼠培养心肌细胞,采用实时荧光定量分析（real-time PCR）检测各组心肌细胞calumenin及内质网应激伴侣蛋白GRP78、GRP94 mRNA表达。结果：①与对照组比较,模型组心肌细胞calumenin mRNA表达减少（P<0.05）,而calumenin基因沉默模型组及黄芪组2心肌细胞calumenin mRNA表达明显减少（P<0.01）;与模型组比较,黄芪组1心肌细胞calumenin mRNA表达增加（P<0.05）;与calumenin基因沉默模型组比较,黄芪组2心肌细胞calumenin mRNA表达明显增加（P<0.01）。②与对照组相比较,模型组及calumenin基因沉默模型组心肌细胞内质网应激伴侣蛋白GRP78、GRP94 mRNA表达明显增多（P<0.01）;与模型组比较,黄芪组1心肌细胞GRP78、GRP94 mRNA表达明显减少（P<0.01）;与calumenin基因沉默模型组比较,黄芪组2心肌细胞内质网应激伴侣蛋白GRP78、GRP94 mRNA表达明显减少（P<0.01）。结论：①阿霉素损伤可引起心肌细胞calumenin表达减少。②Calumenin可缓解阿霉素损伤所诱导心肌细胞内质网应激。黄芪注射液可抑制阿霉素损伤所诱导心肌细胞内质网应激,这种作用可能系通过calumenin介导实现的。     

加兰他敏对间歇性低氧引起的认知损害的预防作用

目的:探究加兰他敏对间歇性低氧引起的认知损伤是否有保护作用,从而说明其对睡眠呼吸暂停综合症引起的认知损害是否有预防作用。方法:建立间歇低氧大鼠模型,行水迷宫试验检测行为功能变化,免疫组化检测海马神经元及胶质细胞数目的变化。结果:加兰他敏与间歇低氧模型组相比,行水迷宫的平均逃避潜伏期缩短,游泳总距离减少;免疫组化的结果海马神经元的数目有所增加,胶质细胞的数目减少。结论:加兰他敏对间歇性低氧引起的认知损伤有明显的改善作用,可能与减少神经元的丢失及减少胶质细胞的再生有关。所以对于诊断了睡眠呼吸暂停综合征(ASA)的患者,如果同时合并其他痴呆的易感因素,可预防性应用加兰他敏。     

miRNA378*表达对柯萨奇B3病毒感染乳鼠心肌细胞凋亡、网腔钙结合蛋白、内质网应激伴侣蛋白表达的影响

目的：研究沉默miRNA378^*表达对柯萨奇B3病毒（CVB3）感染心肌细胞凋亡、内质网应激、网腔钙结合蛋白（calumenin）影响。方法：原代培养乳鼠心肌细胞分为：对照组（正常细胞）、柯萨奇病毒感染组（正常细胞+柯萨奇B3病毒）、miRNA378^*沉默对照组（正常细胞+柯萨奇B3病毒+转染miRNA378^*空质粒）、miRNA378^*沉默组（正常细胞+柯萨奇B3病毒+转染miRNA378^*沉默质粒）,各组细胞分别转染和感染处理后置37℃、CO₂培养箱中培养3 d。检测细胞α-平滑肌肌动蛋白（α-SMA）、细胞凋亡率、网腔钙结合蛋白、葡萄糖调节蛋白78（GRP78）及内质网应激信号通路因子激活转录因子6（ATF6）、转录因子C/EBP同源蛋白（CHOP）的表达。结果：通过检测ɑ-SMA蛋白,证实分离乳鼠细胞为心室肌细胞。TUNEL法检测不同组心室细胞凋亡情况发现,柯萨奇病毒感染组心室肌细胞凋亡明显,与柯萨奇病毒感染组心肌细胞相比较,miRNA378^*沉默组心肌细胞凋亡细胞量明显减少。与柯萨奇病毒感染组比较,Calumenin表达减少（P<0.01）,而GRP78、ATF6、CHOP表达增加（P<0.01）。结论：CVB3病毒感染心肌细胞作用与miRNA378^*,引发内质网应激并激活信号通路因子,心肌细胞凋亡增加。     

Xanthophyll cycle and energy-dependent fluorescence quenching in leaves from pea plants grown under intermittent light

The possible role of zeaxanthin formation and antenna proteins in energy-dependent chlorophyll fluorescence quenching (qE) has been investigated. Intermittent-light-grown pea (Pisum sativum L.) plants that lack most of the chlorophyll a/b antenna proteins exhibited a significantly reduced qE upon illumination with respect to control plants. On the other hand, the violaxanthin content related to the number of reaction centers and to xanthophyll cycle activity, i.e. the conversion of violaxanthin into zeaxanthin, was found to be increased in the antenna-protein-depleted plants. Western blot analyses indicated that, with the exception of CP 26, the content of all chlorophyll a/b-binding proteins in these plants is reduced to less than 10% of control values. The results indicate that chlorophyll a/b-binding antenna proteins are involved in the energy-dependent fluorescence quenching but that only a part of qE can be attributed to quenching by chlorophyll a/b-binding proteins. It seems very unlikely that xanthophylls are exclusively responsible for the qE mechanism.Abbreviations CAB chlorophyll a/b-binding - Chl chlorophyll - F_V variable fluorescence - IML intermittent light - LHC light harvesting complex - PFD photon flux density - qP photochemical quenching of chlorophyll fluoresence - qN non-photochemical quenching - qE energy-dependent quenching - qI photoinhibitory quenching - qT quenching by state transition