对骨细胞生物学功能的最新认识

骨细胞长久以来都被看作是一种终末分化的、代谢隋性的、深埋在骨基质之中的占位细胞．并不具有重要的生理作用和功能。然而近些年的研究发现,骨细胞是一种活跃的多功能细胞,参与机体诸多生物学过程的调控。骨细胞的生物学功能可以大致归纳为以下六类：调节骨重建平衡、感知和转导力学刺激、参与机体的神经-内分泌调节、与肌肉组织有密切的相互作用、降解与合成骨基质及调控骨组织内储存的钙和其他生物活性物质。     

Risks of hormonally active pharmaceuticals to amphibians: a growing concern regarding progestagens

Most amphibians breed in water, including the terrestrial species, and may therefore be exposed to water-borne pharmaceuticals during critical phases of the reproductive cycle, i.e. sex differentiation and gamete maturation. The objectives of this paper were to (i) review available literature regarding adverse effects of hormonally active pharmaceuticals on amphibians, with special reference to environmentally relevant exposure levels and (ii) expand the knowledge on toxicity of progestagens in amphibians by determining effects of norethindrone (NET) and progesterone (P) exposure to 0, 1, 10 or 100 ng l⁻¹ (nominal) on oogenesis in the test species Xenopus tropicalis. Very little information was found on toxicity of environmentally relevant concentrations of pharmaceuticals on amphibians. Research has shown that environmental concentrations (1.8 ng l⁻¹) of the pharmaceutical oestrogen ethinylestradiol (EE₂) cause developmental reproductive toxicity involving impaired spermatogenesis in frogs. Recently, it was found that the progestagen levonorgestrel (LNG) inhibited oogenesis in frogs by interrupting the formation of vitellogenic oocytes at an environmentally relevant concentration (1.3 ng l⁻¹). Results from the present study revealed that 1 ng NET l⁻¹ and 10 ng P l⁻¹ caused reduced proportions of vitellogenic oocytes and increased proportions of previtellogenic oocytes compared with the controls, thereby indicating inhibited vitellogenesis. Hence, the available literature shows that the oestrogen EE₂ and the progestagens LNG, NET and P impair reproductive functions in amphibians at environmentally relevant exposure concentrations. The progestagens are of particular concern given their prevalence, the range of compounds and that several of them (LNG, NET and P) share the same target (oogenesis) at environmental exposure concentrations, indicating a risk for adverse effects on fertility in exposed wild amphibians.     

CFTR: a missing link between exocrine and endocrine pancreas?

<正>Cystic fibrosis(CF),a life-shortening hereditary disease mainly afflicting people of Caucasian origins,is caused by loss-of-function mutations in the CFTR(Cystic Fibrosis Transmembrane conductance Regulator)gene,which encodes a phosphorylation-activated,but ATP-gated anion channel expressed primarily in epithelial cells.To date,nearly 2000 mutations have been identified as pathogenic,     

Direct action of endocrine disrupting chemicals on human sperm

Synthetic endocrine disrupting chemicals (EDCs), omnipresent in food, household, and personal care products, have been implicated in adverse trends in human reproduction, including infertility and increasing demand for assisted reproduction. Here, we study the action of 96 ubiquitous EDCs on human sperm. We show that structurally diverse EDCs activate the sperm‐specific CatSper channel and, thereby, evoke an intracellular Ca²⁺ increase, a motility response, and acrosomal exocytosis. Moreover, EDCs desensitize sperm for physiological CatSper ligands and cooperate in low‐dose mixtures to elevate Ca²⁺ levels in sperm. We conclude that EDCs interfere with various sperm functions and, thereby, might impair human fertilization.     

Semi-automated Imaging of Tissue-specific Fluorescence in Zebrafish Embryos

Zebrafish embryos are a powerful tool for large-scale screening of small molecules. Transgenic zebrafish that express fluorescent reporter proteins are frequently used to identify chemicals that modulate gene expression. Chemical screens that assay fluorescence in live zebrafish often rely on expensive, specialized equipment for high content screening. We describe a procedure using a standard epifluorescence microscope with a motorized stage to automatically image zebrafish embryos and detect tissue-specific fluorescence. Using transgenic zebrafish that report estrogen receptor activity via expression of GFP, we developed a semi-automated procedure to screen for estrogen receptor ligands that activate the reporter in a tissue-specific manner. In this video we describe procedures for arraying zebrafish embryos at 24-48 hours post fertilization (hpf) in a 96-well plate and adding small molecules that bind estrogen receptors. At 72-96 hpf, images of each well from the entire plate are automatically collected and manually inspected for tissue-specific fluorescence. This protocol demonstrates the ability to detect estrogens that activate receptors in heart valves but not in liver.     

The endocrine pancreas in the adult gray short-tailed opossum, Monodelphis domestica (Marsupialia)

Monodelphis domestica, a South American marsupial proposed as a laboratory animal, presents some characteristics that are favourable for research on the development of pancreatic tissue. Therefore, it is important to know if Monodelphis domestica is similar to other mammals concerning the cellular composition of the pancreas and if the different regions of the organ share similar morphologic features. In the present study the pancreas of ten adult male or female Monodelphis domestica were examined: serial paraffin sections were stained immunohistochemically using polyclonal antibodies against insulin or glucagon. The size of the immunoreactive area was measured with a computer-based image-analysing system differentiating lobus dexter, corpus pancreatis, and lobus sinister.

The islets' profiles varied in size and shape. The insulin-positive cells were mainly located in the centre of the islets, while the glucagon-positive cells were arranged at the islets' periphery. However, some glucagon-positive cells also occurred in the centre of most islets. On average, 0.66% of the entire pancreatic section area was insulin-positive, while 0.23% was glucagon-positive. Thus, the ratio between glucagon-positive and insulin-positive area was 1:2.9. Differences between the three pancreatic parts, lobus dexter, corpus pancreatis, and lobus sinister, were revealed. In general, the findings compared well with those of species that have a history as laboratory animals, i.e. mice, rats, cats, and dogs.     

光照对鱼类生理活动影响的研究进展

在自然界,光的变化具有稳定性和规律性,它的变动能触发动物的一些生理机制［１］。关于光对鱼类生理活动影响的研究,国内的报道极少,而国外的研究相对多一些。近年来,虽然在这方面的工作取得了一些进展,但从整体上看,还仅仅处在初步探索阶段。本文根据国内外的研究报道,综述了光照对鱼类繁殖、代谢和内分泌活动的影响。１　光照周期对鱼类繁殖的影响光是影响动物繁殖的一个重要生态因子。许多热带鱼类全年繁殖,因为热带地区的昼长基本上是稳定的［２］。大量的实验室工作也证明,光照对动物繁殖的影响不仅因种而异,而且还因动物的…     

Aspiration cytodiagnosis of pancreatic endocrine tumours

We have reviewed fine needle aspirates from 11 patients with pancreatic endocrine tumours and evaluated the diagnostic criteria as well as those proposed in the literature in an attempt to formulate reliable criteria for the cytological diagnosis of these tumours. As expected, no single criterion was reliable for diagnosis: however, cells with rounded or polygonal rather than a columnar shape, cytoplasmic granularity, and eccentricity of round or oval nuclei with a finely stippled, evenly distributed chromatin pattern were features which taken together, usually enabled one to make a reliable diagnosis. A striking feature of the smears was the cellular monotony and absence of pleomorphism of the tumour cells. Immunocytochemistry and electron microscopy identified tumour products and confirmed the diagnosis.     

Immunocytochemical localisation of GABA in endocrine cells of the rat entero-pancreatic system

The occurence of GABA-containing cells in the rat entero-pancreatic system was investigated by using anti-GABA-glutaraldehyde antibodies at the light and electron microscope level. In the pancreas, the B cells showed intense immunoreactivity, contrary to non-B and exocrine cells. Moreover, post-embedding immunogold staining was localised mostly in mitochondria, close to rough endoplasmic reticulum and in the nucleus. The insulin granules appeared non-significantly stained, which suggests the lack of cosecretion of GABA together with insulin. In the duodenum, GABA immunoreactivity was detected in certain endocrine cell types, suggesting a possible interaction with this amino acid. The well established GABAergic innervation in the enteric system was also confirmed by immunolabelling.