Increased Cell Death and Reduced Neural Crest Cell Numbers in Ethanol-Exposed Embryos: Partial Basis for the Fetal Alcohol Syndrome Phenotype

Fetal alcohol syndrome (FAS) is characterized by growth retardation, craniofacial malformations, and heart and neural defects; the cellular and molecular mechanism(s) responsible for ethanol's teratogenicity remains unknown. Although the phenotype suggests that prenatal ethanol exposure perturbs neural crest cell development, direct proof that these cells are an in utero target is still lacking. Previous research suggested that cranial neural crest cells are eliminated by ethanol-induced apoptosis. We tested this hypothesis using a chick embryo model of FAS. A single dose of ethanol, chosen to achieve a concentration of 35–42 mg/dl, was injected in ovo at gastrulation and resulted in growth retardation, craniofacial foreshortening, and disrupted hindbrain segmentation. Ethanol exposure enhanced cell death within areas populated by cranial neural crest cells, particularly in the hindbrain and craniofacial mesenchyme. In contrast, control embryos had limited cell death within these regions. Subsequent immunolabeling with neural crest cell-specific antibody revealed that ethanol treatment resulted in fewer neural crest cell numbers, whereas neural crest migration patterns were unaffected by ethanol. These results suggest that prenatal ethanol exposure leads to loss of cranial neural crest cells. Such a loss could result, in part, in the phenotype characteristic of FAS.     

巨噬细胞对小鼠诱导多能干细胞向肝祖细胞分化的影响

目的探讨巨噬细胞(Mc)对小鼠诱导多能干细胞(iPSCs)向肝祖细胞(HPCs)分化的影响。方法C57BL/6N小鼠24只,采取腹腔冲洗法获得巨噬细胞,收集上清获得巨噬细胞条件培养基(Mc-CDM)。通过激活素A、骨形态发生蛋白4和成纤维细胞生长因子等诱导小鼠iPSCs向HPCs分化。将HPCs的诱导分为两组,一组使用正常培养基,为对照组(Ctrl组);另一组在诱导D5使用Mc-CDM培养基,为实验组(Mc组)。通过形态学、免疫荧光、Western Blot检测方法,比较正常Ctrl组与Mc组HPCs的形态及相关蛋白表达的差异。计量资料两组间比较采用t检验。结果在体外建立了iPSCs来源的HPCs;HPCs具有向肝细胞分化的潜能。免疫荧光结果显示:与第12天的Ctrl组相比,第12天的Mc组的肝祖细胞特异性蛋白CK19的表达显著增高(0.901±0.072 vs 0.686±0.097,t=-3.093,P<0.05);Western Blot结果显示:与第12天Ctrl组相比,第12天Mc组肝祖细胞相关蛋白CK19的表达显著增高(1.922±0.103 vs 1.448±0.012,t=-7.881,P<0.05);同时,第12天Mc组自噬相关蛋白LC3的表达亦显著增高(1.392±0.042 vs 1.101±0.048,t=-5.978,P<0.05)。结论巨噬细胞可促进小鼠iPSCs向HPCs分化,其机制可能与HPCs细胞自噬水平增加有关。     

Alcohol Consumption in Rats Potentiates the Deleterious Effect of Gram-Negative Sepsis on Hepatic Hyaluronan Uptake

The role of hepatic sinusoidal endothelial cells (SECs) in the pathologic changes of the liver associated with alcohol consumption is not fully understood. The measurement of hyaluronan (HA) uptake by the SECs provides a useful means for assessing the functional state of these cells. In this study, we determined the effect of acute and chronic exposure to alcohol in rats in the absence and presence of subcutaneous Escherichia co/i-induced sepsis on plasma HA concentration and HA uptake by the isolated, perfused liver. Rats were administered ethanol (two doses of 0.2 g/100 g body weight, intraperitoneal, 24 and 15 hr before killing) or fed a liquid diet for 8–10 weeks, containing alcohol (36% of the total calories) or dextrin (in isocaloric amounts). Twenty-one hr before euthanizing for liver perfusion, animals were injected subcutaneously with live E. coli (sepsis) or sterile saline (control). Neither acute nor chronic alcohol exposure by themselves altered plasma HA levels. However, both treatments exacerbated the hyperhyaluronanemic effect of sepsis. Thus, in acutely alcohol-treated rats, sepsis induced a 187% (p &< 0.05) increase in plasma levels of HA, whereas in nonalcohol septic rats, the increase was only 54% (p &< 0.05). Likewise, sepsis resulted in a greater increase in the plasma levels of HA (871%) in alcohol-fed rats than it did in liquid diet, control-fed rats (323%, p &< 0.05). The rate of HA uptake by the isolated, perfused liver was not altered by either acute or chronic alcohol exposure. However, alcohol exposure markedly potentiated the inhibitory effect of sepsis on the capacity of the liver to take up HA. Thus, in acutely alcohol-treated rats, sepsis decreased HA uptake (60-80%, p &< 0.05), whereas in the corresponding nonalcoholic control group the decrease was evident only at the beginning of HA infusion. In chronically alcohol-fed rats, sepsis induced an 80% (p &< 0.05) inhibition of HA uptake, whereas in diet-fed control rats the inhibition was only 60% (p &< 0.05). The inhibition by sepsis of HA uptake by the isolated, perfused liver provides an explanation for the previously observed hyperhy-aluronanemia in septic humans and animals. Because alcohol alone does not alter HA metabolism, the results suggest that acute and chronic alcohol exposure influences the communication between liver cells leading to downregulation of HA clearance by SECs.     

Sympathetic Input to Multiple Cell Types in Mouse and Human Colon Produces Region-Specific Responses

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自体骨髓单个核细胞移植治疗扩张型心肌病的临床研究

目的研究自体骨髓单个核细胞(ABMMNCs)经冠状动脉(冠脉)移植对扩张型心肌病(DCM)患者心功能的影响及其安全性。方法16例扩张型心肌病患者,按患者的意愿分成两组移植组(n=10)在药物治疗的同时,通过冠脉转运将ABMMNCs移植入心肌组织内;对照组(n=6)只进行相关的药物治疗;两组在术前和术后6个月分别行超声心动图及动态心电图检查。结果超声心动图检查显示移植组的左心室射血分数(LVEF)较术前明显增高,左心室舒张末期内径(LVDd)、左心室收缩末期内径(LVSd)较术前明显降低,左心房内径(LAD)也较术前明显降低。而对照组的LVEF,LVDd及LVSd虽然较6个月前有所改善,但差异无统计学意义(P>0.05)。术中及术后随访6~12个月均无恶性心律失常和其他合并症发生。结论ABMMNCs经冠脉移植,可以治疗扩张型心肌病,改善心脏功能,而且较为安全。     

Xanthogranulomatous Appendicitis - An Incidental Finding of Localized Pathology

The clinical, histopathological, and electron microscopic features of an unusual case of xanthogranulomatous appendicitis are reported. The patient, a 37-year-old female, presented with typical signs of acute appendicitis and the appendix appeared slightly dilated at laparatomy. The histopathological sections showed numerous xanthoma cells mixed with inspissated fecaliths. Electron microscopy disclosed the presence of xanthoma cells filled with electron-lucent lipid droplets of variable size. The ultrastructural characteristics of these cells enabled the distinction of two types of lipid-laden histiocytes, in relationship to the size of the lipid droplets. Since the lipid droplets were seen also in cells other than histiocytes, it appears that these changes are secondary to a common mechanism,comprising factors such as obstruction, hemorrhage, inflammation,and local hypoxia.     

Lytic Growth of Human Herpesvirus 8: Morphological Aspects

The human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus, is a gamma herpesvirus associated with AIDS-related body cavity-based lymphomas (BCBL), also called primary effusion lymphomas (PEL). These are a rare form of non-Hodgkin lymphomas in which HHV-8 is present, often associated with Epstein-Barr virus (EBV) infection. HHV-8 is also present in a latent state or in a state of low-level persistence in different primary effusion lymphoma-derived cell lines, such BCBL-1 cells, that lack EBV infection. This cell line was induced to produce mature virions by treatment with 12- O -tetradecanoyl phorbol-13-acetate (TPA) and the characteristic ultrastructural features of HHV-8 lytic replication were identified and compared to those of the other members of Herpesviridae family.     

Phagocytosis of Hemozoin (Native and Synthetic Malaria Pigment), and Plasmodium falciparum Intraerythrocyte-Stage Parasites by Human and Mouse Phagocytes

Hemozoin, the detoxification product of hemoglobin heme, piles up as electron-dense material in the food vacuole (FV) of intraerythrocytic malaria parasites (malaria pigment). In infected individuals, pigment is internalized by both circulating and resident phagocytes, thus modulating their functions. Synthetic beta-hematin, prepared in vitro from hematin (ferriprotoporphyrin IX hydroxide) in acidic condition, is spectroscopically identical to hemozoin. In this electron microscopy study, native and synthetic hemozoin also prove to be morphologically indistinguishable (large polygonal crystals with apparent transverse banding) and to undergo the same process when internalized by phagocytes (primarily a direct uptake of crystals, similar to what is described for asbestos fibers). On the contrary,whole parasites appear to follow a classical endocytic pathway. This suggests that there may be differences between the ingestion of free particles and whole parasites in terms of modulation of phagocytes' functions.     

Electron Microscopy Analysis of Early Localization of Cisplatin in Ovarian Carcinoma Cells

Taking advantage of the electron-dense nature of platinum, in this study the authors used an electron microscopy approach to investigate the cellular localization of cisplatin in an ovarian carcinoma cell line. Platinum spots were detected in contact with the plasma membrane and the nuclear envelope as well as in the cytoplasm and nuclear matrices. Contact with the plasma membrane was through a single blunt contact or spanning through the membrane. No sequestration in intracellular vescicles was observed, thereby supporting that phagocytosis and receptor-mediated endocytosis were not occurring. A molecular analysis indicated lack of expression of aquaporin 9, thus excluding its involvement in the membrane translocation of cisplatin. The present data suggest that cisplatin rapidly accumulates in the cell through endocytosis-independent membrane translocation and are consistent with passive diffusion.     

Cathepsins B and L Increased during Response of Periodontal Ligament Cells to Mechanical Stress In Vitro

Cathepsin is a typical and well-characterized lysosomal cysteine protease that, under pathological conditions, is involved in tissue destruction. A recent immunocytochemical study demonstrated that cathepsins B (CAB) and L (CAL) were localized in the periodontal ligament (PDL) of the rat molar, and they were expressed in compressed sites during experimental tooth movement. Further, we demonstrated previously that the levels of CAB and CAL in gingival crevicular fluid increased during orthodontic tooth movement. Therefore, CAB and CAL may play important roles in the process of collagen degradation during orthodontic tooth movement, and our in vitro study examined the secretion of CAB and CAL in PDL cells following mechanical stress. PDL cells were subjected to 0.5, 1.0, 2.0, or 3.0 g/cm² of compression force or an increase in surface area by tension force of 0.28%, 0.95%, 1.72%, or 2.50% for 24 hr. For detection of CAB and CAL in conditioned medium, commercially available ELISA kits were used. We found compression and tension significantly increased the secretions of both CAB and CAL in PDL cells, which were exhibited in a time- and force magnitude-dependent manner. The compression-stimulated secretion of CAB was increased approximately 3-fold and that of CAL 4-fold, as compared with the control. Further, tension-stimulated secretion of CAB was increased by 1.5-fold and that of CAL 2-fold compared with the control. When analyzed using a semiquantitative polymerase chain reaction assay, CAB and CAL mRNA were increased in response to both compression and tension forces. These findings demonstrated that mechanical stress (compression and tension forces) causes an increase in secretion of CAB and CAL in PDL cells in vitro.