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91.
Fabienne Kinard Lieve de Clercq Brigitte Billen Brigitte Amory Jules-Joseph Hoet Claude Remacle 《In vitro cellular & developmental biology. Plant》1990,26(10):1004-1010
Summary Cell suspensions prepared by collagenase digestion of pancreata obtained from 21.5-d-old rat fetuses were preincubated in
RPMI medium containing 10% fetal bovine serum (FBS), to ensure cell adhesion. Twenty hours later, this medium was replaced
by a chemically defined medium. Dulbecco's modified Eagle's (DME)-F12 was used alone or supplemented with various combinations
of transferrin, sodium selenite, or Ultroser G. The evolution of the culture and the islet ultrastructure were similar in
defined and serum-containing media. However, in the defined medium, the neoformed islets seemed less numerous, and the fibroblast
layer less dense, when compared to the RPMI+10% FBS control medium. At Day 7, in defined media, the total insulin content
per dish was half that of control cultures. None of the tested additives improved the yield of the cultures. The fractional
insulin release per day was elevated in defined media. In subsequent incubations, glucose and leucine stimulated insulin release
in a way characteristic of these cells of fetal origin. The labeling index of islet cells cultured in DME-F12 reached 10.7%,
which is not far from that observed in RPMI+10% FBS. Such a defined medium is useful to study B cell physiology, avoiding
the possible interaction of serum components with substances to be tested.
The support of the Fonds National de la Recherche Scientifique and the ‘Loterie Nationale’ of Belgium is also acknowledged. 相似文献
92.
Jessica S. Vestel Jun-Yan Hong Qingyu Meng Bruce D. Naumann Mark G. Robson Edward V. Sargent 《人类与生态风险评估》2017,23(4):879-894
The presence of synthetic glucocorticosteroids (GCs) in surface water and their potential endocrine disruption (ED) activity at environmental concentrations has not been fully investigated. Synthetic GCs may interfere with endogenous receptors within the hypothalamic-pituitary-gonadal (HPG) axis and disruptions of this pathway can result in decreased reproduction and/or adverse developmental effects. Betamethasone, a synthetic GC, has been on the market in the United States since the 1980's. The Pharmaceutical Assessment and Transport Evaluation model estimated betamethasone concentrations to be <0.6 ng/L in 95% of all U.S. surface waters. Concentrations of 0.01, 0.1, and 1.0 µg betamethasone/L were used in a two-generation fish full life cycle study with Japanese medaka. Gross endpoints, secondary sexual characteristics, and vitellogenin expression were evaluated. The highest concentration at which ED outcomes are not anticipated was determined to be 0.1 µg/L. The ratio of the predicted environmental concentration to the no effect concentration for ED is less than one, indicating no risk to aquatic life from environmentally relevant concentrations of betamethasone. 相似文献
93.
Butterfly wing color patterns can be modified by the application of temperature shock to pupae immediately after pupation, which has been attributed to a cold-shock-induced humoral factor called cold-shock hormone (CSH). Here, we physiologically characterized CSH and pharmacological action of tungstate, using a nymphalid butterfly Junonia orithya. We first showed that the precise patterns of modification were dependent on the time-point of the cold-shock treatment after pupation, and confirmed that the modification properties induced in a cold-shocked pupa were able to be transferred to another pupa in a parabiosis experiment. Cold-shock application after removal of the head and prothorax together still produced modified wings, excluding major involvement of the brain-retrocerebral neuroendocrine complex. Furthermore, tungstate injection induced modifications even in individuals whose head and prothorax were removed. Importantly, transplantation of tracheae isolated from cold-shocked pupae induced modifications in the recipient wings. We identified a chemical peak in hemolymph of the cold-shocked individuals using HPLC, which corresponded to dopamine, and demonstrated that dopamine and its related biogenic amines have ability to induce small color-pattern changes. Taken together, the present study suggests that CSH is likely to be secreted from trachea-associated endocrine cells upon cold-shock treatment and that tungstate may change color patterns via its direct action on wings. 相似文献
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97.
Watanabe T Sakai Y Koga D Bochimoto H Hira Y Hosaka M Ushiki T 《The journal of histochemistry and cytochemistry》2012,60(8):588-602
In polarized exocrine cells, the Golgi apparatus is cup-shaped and its convex and concave surfaces are designated as cis and trans faces, functionally confronting the rough endoplasmic reticulum and the cell surface, respectively. To clarify the morphological characteristics of the Golgi apparatus in non-polarized endocrine cells, the investigators immunocytochemically examined its precise architecture in pituitary gonadotropes, especially in relation to the arrangement of the intracellular microtubule network. The Golgi apparatus in the gonadotropes was not cup-shaped but ball-shaped or spherical, and its outer and inner surfaces were the cis and trans faces, respectively. Centrioles were situated at the center of the Golgi apparatus, from which radiating microtubules isotropically extended to the cell periphery through the gaps in the spherical wall of the Golgi stack. The shape of the Golgi apparatus and the arrangement of microtubules demonstrated in the present study could explain the microtubule-dependent movements of tubulovesicular carriers and granules within the gonadotropes. Furthermore, the spherical shape of the Golgi apparatus possibly reflects the highly symmetrical arrangement of microtubule arrays, as well as the poor polarity in the cell surface of pituitary gonadotropes. 相似文献
98.
1型多发性内分泌瘤综合征(multiple endocrine neoplasia type1,MEN1)是一种主要以累及甲状旁腺、胰岛细胞和垂体的家族性常染色体显性遗传性肿瘤疾病,其致病基因是Men1的基因突变。目前在MEN1患者中发现了大量Men1基因突变位点,其中9个位点突变频率较高,占据所有胚系细胞突变的20%,同时,MEN1患者中还存在Men1基因大片段的外显子缺失,具有外显率高和临床表现多样化的特点,与1型多发性内分泌瘤以及零散型内分泌肿瘤都可能相关。因此,在部分疑似MEN1患者中开展Men1基因变异分析可辅助确诊,在Men1基因突变携带者及其家属中开展Men1变异筛选将有助于对MEN1发生做好提前预防和治疗。 相似文献
99.
Artificial insemination (AI) is an important component of captive breeding programs for endangered species, such as the giant panda. The panda has been the subject of increasingly successful captive breeding programs involving a compilation of assisted breeding techniques, including AI using cryopreserved spermatozoa. AI implementation is currently hampered by a lack of understanding of the factors that may cause failure. We investigated factors influencing the probability of success of AI for 14 giant panda females housed at the China Center for Research and Conservation of the Giant Panda (CCRCGP) inseminated in a total of 20 instances using cryopreserved spermatozoa from 11 males currently residing in 6 different captive breeding institutions. One of the pandas was the oldest giant panda female to ever successfully conceive from AI (20.5 years old). The success of AI was significantly affected by the timing of AI in relationship to both timing of peak urinary estrogen of the female and percent decline in urinary estrogen between the peak level and the first AI attempt. Our results suggest that the window for successful AI in giant pandas may be narrower than previously suspected, although individual differences in rates of decline in urinary estrogen may reflect some degree of variation in this crucial window across females. Our results are consistent with recent research on pandas and other species that demonstrates the efficacy of cryopreserved spermatozoa for AI and highlights the need for more in‐depth analysis of factors related to female physiology that may influence its success. Zoo Biol 31:561‐573, 2012. © 2011 Wiley Periodicals, Inc. 相似文献
100.
Schwacke LH Zolman ES Balmer BC De Guise S George RC Hoguet J Hohn AA Kucklick JR Lamb S Levin M Litz JA McFee WE Place NJ Townsend FI Wells RS Rowles TK 《Proceedings. Biological sciences / The Royal Society》2012,279(1726):48-57
Polychlorinated biphenyls (PCBs), persistent chemicals widely used for industrial purposes, have been banned in most parts of the world for decades. Owing to their bioaccumulative nature, PCBs are still found in high concentrations in marine mammals, particularly those that occupy upper trophic positions. While PCB-related health effects have been well-documented in some mammals, studies among dolphins and whales are limited. We conducted health evaluations of bottlenose dolphins (Tursiops truncatus) near a site on the Georgia, United States coast heavily contaminated by Aroclor 1268, an uncommon PCB mixture primarily comprised of octa- through deca-chlorobiphenyl congeners. A high proportion (26%) of sampled dolphins suffered anaemia, a finding previously reported from primate laboratory studies using high doses of a more common PCB mixture, Aroclor 1254. In addition, the dolphins showed reduced thyroid hormone levels and total thyroxine, free thyroxine and triiodothyronine negatively correlated with PCB concentration measured in blubber (p = 0.039, < 0.001, 0.009, respectively). Similarly, T-lymphocyte proliferation and indices of innate immunity decreased with blubber PCB concentration, suggesting an increased susceptibility to infectious disease. Other persistent contaminants such as DDT which could potentially confound results were similar in the Georgia dolphins when compared with previously sampled reference sites, and therefore probably did not contribute to the observed correlations. Our results clearly demonstrate that dolphins are vulnerable to PCB-related toxic effects, at least partially mediated through the endocrine system. The severity of the effects suggests that the PCB mixture to which the Georgia dolphins were exposed has substantial toxic potential and further studies are warranted to elucidate mechanisms and potential impacts on other top-level predators, including humans, who regularly consume fish from the same marine waters. 相似文献