Biological activity of Burkholderia (Pseudomonas) cepacia lipopolysaccharide

Abstract Burkholderia cepacia has emerged as an important multiresistant pathogen in cystic fibrosis (CF), associated in 20% of colonised patients with a rapid and fatal decline in lung function. Although knowledge of B. cepacia epidemiology has improved, the mechanisms involved in pathogenesis remain obscure. In this study, B. cepacia lipopolysaccharide (LPS) was assessed for endotoxic potential and the capacity to induce tumour necrosis factor (TNF). LPS preparations from clinical and environmental isolates of B. cepacia and from the closely related species Burkholderia gladioli exhibited a higher endotoxic activity and more pronounced cytokine response in vitro compared to preparations from the major CF pathogen Pseudomonas aeruginosa . This study may help to explain the vicious host immune response observed during pulmonary exacerbations in CF patients colonised by B. cepacia and lead to therapeutic advances in clinical management.     

Ultrastructure of retrocerebral complex of the earwig, Euborellia annulipes, and rôle of aorta as a neurohaemal organ

The ultrastructure of the retrocerebral endocrine-aortal complex of the earwig, Euborellia annulipes has been studied. The space between the inner and outer stromal layers of the aorta is occupied by numerous axon terminals and pre-terminals containing large electron dense granules (NS-I) of approximately 100 to 220 nm and a few axon terminals having small granules (NS-II) of approximately 40 to 90 nm; the former appear to belong to medial neurosecretory A-cells, and the latter to the B-cells of the brain. The corpora cardiaca consist of intrinsic cells with mitochondria and multivesicular bodies. Granules of type NS-II and NS-III are observed in the axon terminals and pre-terminals in the corpora cardiaca. The NS-II are identical to those found in the aorta and are probably the secretions of the lateral B-cells. Granules of type NS-III are 40 to 120 nm and electron dense, and are intrinsic in origin. Similar granules occur in the intrinsic cells of the corpora cardiaca. E M studies have confirmed the rôle of the aorta as a neurohaemal organ for the medial neurosecretory cells, and the corpora cardiaca for the lateral neurosecretory cells of the brain. The corpora cardiaca also act as a reservoir for the intrinsic secretion. The corpus allatum is a solid body consisting of parenchymal cells with prominent nuclei, mitochondria, and endoplasmic reticulum. In between its cells are occasional glial cells and also neurosecretory as well as non-neurosecretory axons. The gland is devoid of A-cell NSM.     

Catalase deficiency may complicate urate oxidase (rasburicase) therapy

Patients with low (inherited and acquired) catalase activities who are treated with infusion of uric acid oxidase because they are at risk of tumour lysis syndrome may experience very high concentrations of hydrogen peroxide. They may suffer from methemoglobinaemia and haemolytic anaemia which may be attributed either to deficiency of glucose-6-phosphate dehydrogenase or to other unknown circumstances. Data have not been reported from catalase deficient patients who were treated with uric acid oxidase. It may be hypothesized that their decreased blood catalase could lead to the increased concentration of hydrogen peroxide which may cause haemolysis and formation of methemoglobin. Blood catalase activity should be measured for patients at risk of tumour lysis syndrome prior to uric acid oxidase treatment.     

Isolation of Primary Myofibroblasts from Mouse and Human Colon Tissue

The myofibroblast is a stromal cell of the gastrointestinal (GI) tract that has been gaining considerable attention for its critical role in many GI functions. While several myofibroblast cell lines are commercially available to study these cells in vitro, research results from a cell line exposed to experimental cell culture conditions have inherent limitations due to the overly reductionist nature of the work. Use of primary myofibroblasts offers a great advantage in terms of confirming experimental findings identified in a cell line. Isolation of primary myofibroblasts from an animal model allows for the study of myofibroblasts under conditions that more closely mimic the disease state being studied. Isolation of primary myofibroblasts from human colon tissue provides arguably the most relevant experimental data, since the cells come directly from patients with the underlying disease. We describe a well-established technique that can be utilized to isolate primary myofibroblasts from both mouse and human colon tissue. These isolated cells have been characterized to be alpha-smooth muscle actin and vimentin-positive, and desmin-negative, consistent with subepithelial intestinal myofibroblasts. Primary myofibroblast cells can be grown in cell culture and used for experimental purposes over a limited number of passages.     

脂肪酸生物标记法研究零排放猪舍基质垫层微生物群落多样性

用微生物群落脂肪酸生物标记总量,分析零排放猪舍基质垫层微生物群落的数量变化,日本洛东微生物菌种处理组和零排放I号菌种处理组各层微生物脂肪酸生物标记含量变化趋势相近。基质垫层微生物群落脂肪酸生物标记检测出37个生物标记,构成微生物群落的指纹图谱,含量最高的前4个生物标记为：细菌16：00含量为431260,细菌18：1ω9c含量为413075,厌氧细菌18：1ω7c含量为101368,耗氧细菌i15：0含量为90328.不同的生物标记多样性指数在基质垫层不同层次分布不同,可作为衡量特定微生物生物标记功能的一个指标。通过基质垫层微生物脂肪酸生物标记特征指数B的分析,提出了微生物群落分布的特征指标,生物标记特征指数B越高,表明微生物群落中的细菌和真菌含量越高,有利于基质垫层分解粪便排泄物,可作为基质垫层微生物群落变化优劣的特征性指标;通过基质垫层耗氧细菌和厌氧细菌脂肪酸生物标记含量比值,构建发酵指数F,作为基质垫层发酵特性的指标,发酵指数F越高,表明耗氧细菌起的作用越大,反之,耗氧细菌起的作用越小,生物标记的发酵指数可以作为研究粪便排泄物的微生物分解过程的指数。     

Effect of interferon γ and tumour necrosis factor α on sensitivity to cisplatin in ovarian carcinoma cell lines

This study aimed to investigate whether the biological response modifiers (BRM) interferon (IFN) and tumour necrosis factor (TNF) could enhance the cytotoxic action of cisplatin on ovarian tumour cells in vitro. The sensitivity of four cell lines (OAW42, GG, JAM and PE01) to drugs and drug combinations was tested by a radiolabelled-thymidine incorporation assay. Cell lines demonstrated a range of sensitivity to cisplatin and the innate cytotoxic effect of each of the BRM. When IFN was used in combination with cisplatin, a significant enhancement of cisplatin toxicity occurred in three of four cell lines. TNF demonstrated such an effect in two cell lines but diminished the toxicity of cisplatin in one cell line. A purely additive effect of the agents may explain the enhanced toxicity of cisplatin in some of these cases. However, in one cell line at least (PEO1), both TNF and IFN demonstrated a clearly synergistic effect with cisplatin. These BRM used in conjunction with cisplatin may provide better antitumour regimen than cisplatin alone in some patients with ovarian cancer, but the response is likely to be heterogeneous between patients.