The contribution of <Emphasis Type="Italic">Potamogeton crispus</Emphasis> to the phosphorus budget of an urban shallow lake: Lake Monger,Western Australia

Lake Monger (Perth, Western Australia) is a highly eutrophic lake, characterised by very low species richness of macrophytes with the dominance of Potamogeton crispus. Mesocosm experiments were performed using water and plants collected from the lake to determine the effects of vegetation decay on the phosphorus (P) concentrations in the overlying waters. After 2 weeks of experimental incubation of mesocosms with and without re-oxygenation, P concentrations in the water column were significantly higher, showing a quite similar effect of P. crispus on the phosphorus release in different mesocosms. The results of our study provide clear evidence that the P concentrations in overlying waters mainly depend upon the plant P content and developmental stage. Although many sources contribute to the nutrient load of Lake Monger, macrophyte harvesting, prior to its senescence, might constitute a significant in-lake measure for reducing the internal P load.     

Comparison of selective procedures for isolation and enumeration of Legionella species from hot water systems

E. LEONI AND P.P. LEGNANI. 2001 . Various sample pre-treatment techniques and different growth media for the isolation of Legionellae from hot water supplies in public buildings were compared. A total of 102 hot water samples from taps and showers was examined. The highest recovery frequency was obtained with the heat pre-treatment method and using the selective medium GVPC. However, the results differed according to the concentration of legionellas. In the case of low plate counts (≤5000 cfu l⁻¹), the heat pre-treatment technique gave a significantly higher percentage of positive samples compared with other techniques ( P  < 0·05). With increasing concentration, the differences between the procedures decreased until they became statistically not significant for concentrations above 50 000 cfu l⁻¹. The direct inoculum method allowed a significantly higher detection of concentrations ( P  < 0·001) compared with heat and acid decontamination methods, which brought about a 67–68% reduction in detectable Legionellae. Heat decontamination techniques show greater sensitivity and specificity. However, they underestimate the number of legionellas. In environmental surveillance programmes, this underestimate must be taken into consideration when assessing the health risk.     

Effect of vitrification solutions and cooling upon in vitro matured prepubertal ovine oocytes

The vitrification procedure effects on molecular and cytoskeletal components and on developmental ability of in vitro matured prepubertal ovine oocytes were evaluated. MII oocytes were divided into three groups: (1) vitrified in cryoloops (VTR); (2) exposed to vitrification solutions and rehydrated without being plunged into liquid nitrogen (EXP); (3) without further treatment as a control (CTR). Two hours after treatment, membrane integrity, assessed by propidium iodide/Hoechst staining, was lower in VTR and EXP than in CTR (70.6%, 88.5% and 95.2%, respectively). Cleavage rate after fertilization was statistically different among all groups (21.4%, 45.4% and 82.8% for VTR, EXP and CTR groups respectively; P<0.01). Blastocyst rate in VTR (0.0%) and EXP (2.8%) groups was lower (P<0.01) than in CTR (22.8%). Maturation promoting factor activity was lower (P<0.01) in VTR and EXP groups compared with CTR at both 0 h (82.2%, 83.6% and 100%, respectively) and 2 h (60% and 53.9% and 100%, respectively) after warming. Immediately after warming VTR and EXP oocytes showed a lower rate of normal spindle and chromosome configuration compared to CTR (59.1%, 48.0% and 83.3%, respectively; P<0.01). After 2 h of culture in standard conditions the percentage of oocytes with normal spindle and chromosome organization decreased in both VTR and EXP groups compared to CTR (36.4%, 42.8% versus 87.5%, respectively). In conclusion the exposition to the tested cryoprotectant solution and the vitrification in cryoloops modified cytoskeletal components and alter biochemical pathways that compromise the developmental capacity of prepubertal in vitro matured ovine oocytes.     

Characterization and modulation of fibroblast/endothelial cell co-cultures for the in vitro preformation of three-dimensional tubular networks

Various assays of different complexity are used in research on angiogenesis in health and disease. The results of these assays increasingly impact the field of tissue engineering because preformed microvascular networks may connect and conduct to the vascular system of the host, thereby helping us to support the survival of implanted cells and tissue constructs. An interesting model that supports the formation of EC (endothelial cells) tubular structures in vitro is based on co-culturing them with fibroblasts. Our initial multilayer approach was recently transferred into a three-dimensional spheroid model using HUVEC (human umbilical vein endothelial cells) as model cells. The aim of the present study is to further characterize, extend and validate this fibroblast/EC spheroid co-culture system. We have evaluated the model with a maximum size of 600-650 μm attained on day 3 from inoculation of 4×104 fibroblasts with 1×104 EC. Cell count and spheroid diameter significantly decreased as a function of time, but the EC network that developed over a period of 14 days in culture was clearly visible and viable, and central cell death was excluded. We successfully included HMVEC (human microvascular endothelial cells) of dermal origin in the system and replaced FBS (fetal bovine serum) with human AB serum, which positively impacted the EC network formation at optimized concentrations. The need for exogenous growth factors [VEGF (vascular endothelial growth factor), EGF (epithelial growth factor), bFGF (basic fibroblast growth factor) and IGF-1 (insulin-like growth factor-1)] routinely added to classical EC media was also assessed. The behaviour of both fibroblasts and EC in response to a combination of these exogenous growth factors differed critically in fibroblast/EC spheroid co-cultures compared with the same cells in the multilayer approach. VEGF was the most relevant exogenous factor for EC network formation in fibroblast/EC multilayers, but was ineffective in the spheroid system. IGF-1 was found, in general, to be dispensable; however, while it had a negative impact on EC networking in the presence of bFGF and EGF in the multilayer, it did not in the spheroid approach. We conclude that the critical determinants of EC network formation and cell survival are not universal, but have to be specifically optimized for each culture model.     

Pharmacokinetics, safety and inducible cytokine responses during a phase 1 trial of the oral histone deacetylase inhibitor ITF2357 (givinostat)

ITF2357 (givinostat) is a histone deacetylase inhibitor with antiinflammatory properties at low nanomolar concentrations. We report here a phase I safety and pharmacokinetics trial in healthy males administered 50, 100, 200, 400 or 600 mg orally. After 50 mg, mean maximal plasma concentrations reached 104 nmol/L 2 h after dosing, with a half-life of 6.9 h. After 100 mg, maximal concentration reached 199 nmol/L at 2.1 h with a half-life of 6.0 h. Repeat doses for 7 consecutive days of 50, 100 or 200 mg resulted in nearly the same kinetics. There were no serious adverse effects (AEs) and no organ toxicities. However, there was a dose-dependent but transient fall in platelets. After 7 daily doses of 50 or 100 mg, the mean decrease in platelets of 17 and 25% was not statistically significant and returned to baseline within 14 d. Blood removed from the subjects after oral dosing was cultured ex vivo with endotoxin, and the release of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-1Ra, interferon (IFN)-γ and IL-10 was determined. Maximal reduction in IL-1β, TNFα, IL-6 and IFNγ was observed 4 h after dosing but returned to baseline at 12 h. There was no significant reduction in IL-1Ra or IL-10. With daily dosing, the fall in cytokine production in blood cultures observed on day 7 was nearly the same as that of the first day. We conclude that dosing of 50 or 100 mg ITF2357 is safe in healthy humans and transiently but repeatedly reduces the production of proinflammatory cytokines without affecting production of antiinflammatory cytokines.     

越南苦苣苔科石蝴蝶属植物随记暨国家级分布新记录

石蝴蝶属(Petrocosmea Oliv.)植物的现代分布与分化中心位于中国的西南山地以及周边国家和地区,如印度(阿萨姆邦)、缅甸、泰国、越南等也有分布。近年来,中国和中南半岛上各个国家和地区的新分类群和国家级新记录层出不穷,进一步加深了研究人员对中国和中南半岛植物区系以及该属植物在上述区域的多样性的理解。例如,滇黔石蝴蝶[Petrocosmea martinii (H. Léveillé)H. Léveillé]和丝毛石蝴蝶(P. sericea C.Y. Wu ex H. W. Li)曾被认为是中国的特有种,前者分布于贵州、广西北部和云南东南部,而后者仅见于云南东南部。该文报道了这两种石蝴蝶属植物的越南国家级分布新记录。这两个新记录种的发现,使得越南分布的石蝴蝶属植物种的数量上升到了5 种,这些新记录种的报道或暗示未来在与中国西南山地邻近的地区还将会有更多该属的新分类群或新记录有待发现。该文还同时提供了这两个国家级分布新记录物种的描述、图示、濒危等级现状评价以及目前所有越南已知分布的石蝴蝶属植物的检索表以备检索和核对。