Natural occurrence of neoplastic lesions in young sprague-dawley rats

It is important for the assessment of toxicological effects of chemicals to know what kinds of neoplasms naturally occur in the early life of experimental animals. In the present study, we demonstrated spontaneous neoplasms in Sprague-Dawley rats used in 4-, 13- and 26-week toxicity studies conducted at Bozo Research Center in the last decade. The tumors, which were first observed in 19-week-old animals, included anterior adenoma of the pituitary, follicular cell adenocarcinoma and C cell adenoma of the thyroids, nephroblastoma of the kidneys, basal cell tumor of the skin and malignant lymphoma. Thereafter, hemangiosarcoma of the tongue, adenocarcinoma of the submandibular glands, histiocytic sarcoma of the spleen, oligodendroglioma of the brain and adenocarcinoma and fibroadenoma of the mammary glands were detected in 32-week-old animals. The incidences of mammary adenocarcinoma and pituitary anterior adenoma were higher than those of other tumors. The present results showed that the same tumors as reported in aged rats could also develop in younger rats.     

影响乳脂自发性氧化反应的主要因素

乳脂的自发性氧化反应可以导致牛乳风味异常,其主要源于乳脂中不饱和脂肪酸的自发性氧化反应.本文就乳脂发生自发性氧化反应的机制及其原因进行简要的概述,以期引起人们对乳脂自发性氧化反应研究的重视.     

中度嗜热菌Deinococcus geothermalis的自发突变特征

通过rpoB/Rifr系统研究了Deinococcus geothermalis DSM 11300的自发突变模式。在30℃和50℃分别获得自发突变株并测定其相应温度条件下的突变频率和突变率。结果表明,30℃培养下该菌的自发突变率是50℃培养的2倍,二者有22个不同的突变位点,表明温度影响了该菌的自发突变。此外,50℃...     

Effects of diet on spontaneous locomotor activity and oxygen consumption in Adriatic sturgeon (Acipenser naccarii)

Adriatic sturgeon (Acipenser naccarii) were maintained on a commercial diet enriched either in long chain polyunsaturated fatty acids of the 3 series (3 LCPUFA) or in saturated fatty acids (SFA). The effects of dietary fatty acid composition on spontaneous locomotor activity in normoxia and hypoxia (O₂ tension = 10.5 ± 0.8 kPa), and on oxygen consumption (M^O ₂) in normoxia, in hypoxia (O₂ tension = 6.6 ± 0.8 kPa) and during recovery were then investigated. The effects of adding supplementary vitamin E to the fat-enriched diets were also studied.Dietary fatty acid composition had effects on spontaneous locomotor activity and M^O ₂ in normoxia. Activity levels were higher in all sturgeon fed extra dietary fats (without vitamin E), when compared with control animals, but fish fed 3 LCPUFA had a significantly lower M^O ₂ than those fed SFA, with intermediate M^O ₂ in controls. In hypoxia, sturgeon 3 LCPUFA did not alter activity or M^O ₂ whereas those fed SFA reduced both and controls reduced M^O ₂. During recovery, both animals fed SFA and controls had a higher M^O ₂ than sturgeon fed 3 LCPUFA. The data indicate that fish fed 3 LCPUFA are more tolerant of hypoxia than controls or those fed SFA, as they did not reduce either activity or M^O ₂, and consumed less O₂ during recovery.Vitamin E supplements modified the effects elicited by dietary fats. All sturgeon fed vitamin E had low activity levels in normoxia and hypoxia. Sturgeon fed vitamin E with 3 LCPUFA had a higher M^O ₂ in normoxia than those fed 3 LCPUFA alone; reduced M^O ₂ in hypoxia, and during recovery increased M^O ₂ to a rate higher than that of animals fed 3 LCPUFA alone. In normoxia, sturgeon fed vitamin E with SFA had a similar M^O ₂ to those fed SFA alone but did not change M^O ₂ in hypoxia or during recovery. Thus, the effects of vitamin E were dependent on fat composition of the diet. Vitamin E with 3 LCPUFA removed the beneficial effects on M^O ₂ and responses to hypoxia obtained with 3 LCPUFA alone, but vitamin E with SFA allowed sturgeon to maintain aerobic metabolism in hypoxia, a more effective response than that observed in fish fed SFA alone.     

Spontaneous Accumulation of Globotriaosylceramide (Gb3) in Proximal Renal Tubules in an ICR Mouse

This report describes spontaneous cytoplasmic vacuolation in the proximal renal tubules of a 7-week-old male ICR [Crlj:CD1(ICR)] mouse. The contents of vacuoles were positively stained with periodic acid-Schiff (PAS) and Sudan black, and the membranes were positive on immunohistochemical staining for lysosomal-associated membrane protein-2 (LAMP-2), a marker of lysosomal membrane. Electron microscopy revealed electron-dense lamellar bodies in the proximal tubular epithelial cells. These histopathological features are similar to those in α-galactosidase A-deficient mice, in which globotriaosylceramide (Gb3), a glycosphingolipid, accumulates in lysosomes. When we performed immunohistochemical staining for Gb3, the contents of vacuoles were positively stained. From these results, spontaneous cytoplasmic vacuolation in the proximal renal tubules in the mouse was identified as lysosomal accumulation of Gb3.     

Spontaneous Extraskeletal Osteosarcoma in a Rabbit (Oryctolagus cuniculus): Histopathological and Immunohistochemical Findings

A spontaneously occurring subcutaneous mass in the left forelimb of a nine-year-old rabbit (Oryctolagus cuniculus) was examined histopathologically and immunohistochemically. Clinically, edema and hemorrhage were seen around the mass. No connection of the tumor mass to the appendicular skeleton was found. The tumor was arranged in a solid growth pattern and irregular bundles, and neoplastic cells were polygonal to spindle-shape. Osteoid (positive for osteocalcin) and multinucleated giant cells were diffusely or focally seen. Neoplastic cells were positive for vimentin, osterix and Ki-67, indicating the nature of osteoblasts with proliferating activity, but negative for α-smooth muscle actin, desmin or CD204. Based on these findings, a diagnosis of extraskeletal osteosarcoma was made, a very rare tumor both in laboratory and pet rabbits.     

Spontaneous Ameloblastic Fibroma in a Young Guinea Pig

A spontaneous ameloblastic fibroma was found in a 9-week-old guinea pig. Histopathologically, neoplastic cells consisted of two components: an odontogenic epithelium and odontogenic mesenchyme. The odontogenic epithelium formed strands, nests and islands that were interspersed within the odontogenic mesenchyme. In the marginal region, odontoblasts and scant dysplastic eosinophilic material were seen between these two components. Immunohistochemically, the odontogenic epithelium was positive for cytokeratin AE1/AE3, and the odontogenic mesenchyme and odontoblast were positive for vimentin, in the same manner as in the normal tooth germ (control). We could not obtain conclusive data suggesting that the eosinophilic material was dental hard tissue because the eosinophilic material was not stained specifically by any methods. Based on these histological characteristics, the tumor in the present case was diagnosed as an ameloblastic fibroma. This is the first report of ameloblastic fibroma in guinea pigs.     

Decidual macrophages modulate trophoblast cells by transferring exosomes in unexplained recurrent spontaneous abortion

AIM: To investigate whether decidual macrophages have ability to regulate trophoblast cells by secreting exosomes in unexplained recurrent spontaneous abortion (URSA). METHODS: The decidual macrophages were isolated from deciduas of URSA and normal early pregnant induced abortion women. Transmission electron microscopy revealed the morphology and size of the macrophages-derived exosomes. Besides, the characterization of the exosomes was confirmed by the presence of known exosomal marker CD63 by Western blot. The HTR8/Snveo cells were treated with exosomes extracted from the decidual macrophages of URSA or normal early pregnanty induced abortion women. Confocal microscopy, MTS assay and Transwell assay were used to explore the effect of URSA macrophages-derived exosomes on viabi-lity and migration ability of trophoblasts cells. RESULTS: Electron microscopy showed exosomes secreted by macrophages displayed a round-shaped appearance, ranging 40~80 nm in diameter. The results of Western blot indicated that exosomes exacted from the macrophages expressed CD63, a member of tetraspanin family protein. Confocal microscopy revealed the exosomes were taken up by the HTR8/Snveo cells. MTS assay indicated the viability of HTR8/Snveo cells was declined when incubated with the URSA macrophages-derived exosomes (P<0.05). In URSA macrophages-derived exosomes group, the migration ability of the HTR8/Snveo cells was decreased significantly as compared with normal early pregnant induced abortion macrophages-derived exosome (P<0.05). CONCLUSION: Decidual macrophages of URSA inhibits the viability and migratory properties of trophoblast cells by exosomes, which participates in regulating maternal-fetal immune in URSA.     

广州市老旧社区自发性种植空间研究

指出了广州市老旧住区,建筑密度高、人口密度大、老年人群较多,社区自发种植较为广泛。对广州市4个典型老旧社区进行实地调研。通过空间类型及使用评价,对广州市老旧住区自发性种植空间特点进行了分析;通过统计分类,对居民植物利用情况进行了总结。从中对城镇化过程中都市空间利用的不同模式在广州老旧住区可发展的潜力进行了初步探讨,为今后老旧社区的更新改造,都市户外绿化空间的地域化发展路径提供参考。     

Sheared heels and the correlation to spontaneous quarter cracks

The strong association between sheared heels and a spontaneous quarter crack is hard to ignore. Although inappropriate farriery may play a role, limb conformation and the landing pattern of the horse appear to be the dominant factors causing this type of hoof capsule deformation. The importance of determining the underlying cause and implementing the appropriate farriery cannot be over emphasised when managing a quarter crack associated with a sheared heel. The repair of spontaneous quarter cracks will be of little value, and the defect will have a tendency to recur, unless the cause is identified and rectified.