循环血中GM-CFC的性能研究

利用造血细胞体外琼脂培养技术,比较了狗的不同来源的GM—CFC增殖、分化性能和辐射敏感性。结果表明,在正常生理条件下循环血中GM—CFC集落产率约为骨髓的1/60;细胞集落开始形成时间较骨髓晚1天,细胞集落随培养时间(前3—5天)增加而增加,其增加速率约为骨髓的20%;辐射敏感性D_0值为0.34Gy,明显低于骨髓中GM—CFC的D_0值(0.82Gy)。造血干细胞动员剂动员后血中GM—CFC数量明显增加,细胞集落增加速率约为骨髓的59%,D_0值为0.72Gy。从而为循环血干细胞移植疗效提供了实验依据。     

Age-related changes in antioxidant enzyme activities and lipid peroxidation in lungs of control and sulfur dioxide exposed rats

Antioxidant defenses within the lung are pivotal in preventing damage from oxidative toxicants. There have also been several reports with conflicting results on the antioxidant system during aging. In this study, we attempted to investigate age-related alterations in both antioxidant enzyme activities and thiobarbituric acid-reactive substances (TBARS), a product of lipid peroxidation, in the whole lung of control and sulfur dioxide (SO₂) exposed rats of different age groups (3-, 12-, and 24-months-old). Swiss-Albino Male rats were exposed to 10 ppm SO₂ 1 hr/day, 7 days/week for 6 weeks. The antioxidant enzymes examined include Cu,Zn-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione S-transferase (GST). A mixed pattern of age-associated alterations in antioxidant activities was observed. SOD, GSH-Px and GST activities were increased with age, but CAT activity was decreased. Lung SOD, GSH-Px and GST activities were also increased in response to SO₂. The level of TBARS was increased with age. SO₂ exposure stimulated lipid peroxide formation in the lung as indicated by an increase in the level of TBARS. These findings suggest that both aging and SO₂ exposure may impose an oxidative stress to the body. We conclude that the increase in the activities of the antioxidant enzymes of the lung during aging, could be interpreted as a positive feedback mechanism in response to rising lipid peroxidation.     

Involvement of G6PDH in heat stress tolerance in the calli from Przewalskia tangutica and Nicotiana tabacum

Glucose-6-phosphate dehydrogenase (G6PDH) has been implicated in supplying reduced nicotine amide cofactors for biochemical reactions and in modulating the redox state of cells. In this study, the role of G6PDH in thermotolerance of the calli from Przewalskia tangutica and tobacco (Nicotiana tabacum L.) was investigated. Results showed that Przewalskia tangutica callus was more sensitive to heat stress than tobacco callus. The activity of G6PDH and antioxidant enzymes (ascorbate peroxidase, catalase, peroxidase and superoxide dismutase) in calli from Przewalskia tangutica and tobacco increased after 40 °C treatment, although two calli exhibited a difference in the degree and timing of response to heat stress. When G6PDH was partially inhibited by glucosamine pretreatment, the antioxidant enzyme activities and thermotolerance in both calli significantly decreased. Simultaneously, the heat-induced H₂O₂ content and the plasma membrane NADPH oxidase activity were also reduced. Application of H₂O₂ increased the activity of G6PDH and antioxidant enzymes in both calli. Diphenylene iodonium, a NADPH oxidase inhibitor, counteracted heatinduced H₂O₂ accumulation and reduced the heat-induced activity of G6PDH and antioxidant enzymes. Moreover, exogenous H₂O₂ was effective in restoring the activity of G6PDH and antioxidant enzymes after glucosamine pretreatment. Western blot analysis showed that G6PDH gene expression in both calli was also stimulated by heat and H₂O₂, and blocked by DPI and glucosamine under heat stress. Taken together, under heat stress G6PDH promoted H₂O₂ accumulation via NADPH oxidase and the elevated H₂O₂ was involved in regulating the activity of antioxidant enzymes, which in turn facilitate to maintain the steady-state H₂O₂ level and protect plants from the oxidative damage.     

Outgrowth promoting factor for the inner cell mass of the mouse blastocyst

When cultured individually, isolated inner cell masses (ICMs) of the mouse blastocyst form an outer layer of endoderm and remain in suspension as spherical structures for several days. Conditioned media from certain teratocarcinoma- and blastocyst-derived cell lines contain one or more outgrowth promoting factors (OPF) which facilitate attachment and outgrowth of ICMs, in some cases prior to endoderm formation. OPF adheres to culture dishes and presumably promotes ICM cell outgrowth by alteration of the substratum. Analyses indicate that the active material is a nondialyzable protein which is stable to freezing and thawing, a wide range of pH, and extended incubation at 37°C. However, inactivation takes place at 60°C for 20 min. Although these properties of OPF are in some ways similar to those of various proteins which have been implicated in cell adhesion and spreading, differences between OPF and most of these other proteins are evident. The detection of OPF activity in conditioned medium from primary cultures of embryonic and some extraembryonic cell types suggests that the factor is biologically significant, perhaps, for example, in the spreading of parietal endoderm cells along the surface of the trophoblast layer.     

Environmental footprints of British Columbia wood pellets from a simplified life cycle analysis

Purpose  

Environmental footprints of wood pellets produced in British Columbia (BC) of Canada are to be estimated based on industry surveys and published emission factor data.     

Isoliquiritigenin ameliorates caerulein‐induced chronic pancreatitis by inhibiting the activation of PSCs and pancreatic infiltration of macrophages

Chronic pancreatitis (CP) is characterized by persistent inflammation of the pancreas that results in progressive loss of the endocrine and exocrine compartment owing to atrophy and/or replacement with fibrotic tissue. Currently, the clinical therapeutic scheme of CP is mainly symptomatic treatment including pancreatic enzyme replacement, glycaemic control and nutritional support therapy, lacking of specific therapeutic drugs for prevention and suppression of inflammation and fibrosis aggravating in CP. Here, we investigated the effect of isoliquiritigenin (ILG), a chalcone‐type dietary compound derived from licorice, on pancreatic fibrosis and inflammation in a model of caerulein‐induced murine CP, and the results indicated that ILG notably alleviated pancreatic fibrosis and infiltration of macrophages. Further in vitro studies in human pancreatic stellate cells (hPSCs) showed that ILG exerted significant inhibition on the proliferation and activation of hPSCs, which may be due to negative regulation of the ERK1/2 and JNK1/2 activities. Moreover, ILG significantly restrained the M1 polarization of macrophages (RAW 264.7) via attenuation of the NF‐κB signalling pathway, whereas the M2 polarization was hardly affected. These findings indicated that ILG might be a potential anti‐inflammatory and anti‐fibrotic therapeutic agent for CP.