Dual energy x-ray absorptiometry analysis contributes to the prediction of hip osteoarthritis progression

Introduction  

To determine if structural bone parameters obtained from dual energy X-ray absorptiometry (DXA) contribute to the prediction of progression of hip osteoarthritis (OA) and to test if the difference between the most affected (OA) hip and the contralateral hip adds to this prediction.     

Variation in the spectrum of Fusarium species on winter wheat

In 1998–2000 a monitoring of the spectrum of Fusarium species on winter wheat was carried out in the Rhineland. The epidemic spread ofFusarium spp. on wheat plants during growing season was investigated as well as the grain contamination after harvest.F avenaceum was the Fusarium species isolated most frequently followed byF culmorum, F poae andF graminearum. Microdochium nivale occurred considerably only in 1998. Both, susceptibility and plant height of the cultivars were correlated to the incidence of Fusarium species /M nivale on harvested kernels; interactions with cropping intensities were detected. The incidence ofF poae seemed to be independent of the cultivar-specific Fusarium susceptibility. Despite the lack of disease symptoms, between growth stages 45–85 mycelium ofFusarium spp. was detectable in the leaves as well as conidia on the leaf surfaces.     

The yeast kinome displays scale free topology with functional hub clusters

Background  

The availability of interaction databases provides an opportunity for researchers to utilize immense amounts of data exclusively in silico. Recently there has been an emphasis on studying the global properties of biological interactions using network analysis. While this type of analysis offers a wide variety of global insights it has surprisingly not been used to examine more localized interactions based on mechanism. In as such we have particular interest in the role of key topological components in signal transduction cascades as they are vital regulators of healthy and diseased cell states.     

Acetoacetate and glucose as substrates for lipid synthesis by rat brain oligodendrocytes and astrocytes in serum-free culture

We have compared glucose and acetoacetate as precursors for lipogenesis and cholesterogenesis by oligodendrocytes and astrocytes, using mixed glial cultures enriched in oligodendrocytes. In order to differentiate between metabolic processes in oligodendrocytes and those in astrocytes, the other major cell type present in the mixed culture, we carried out parallel incubations with cultures from which the oligodendrocytes had been removed by treatment with anti-galactocerebroside serum and guinea-pig complement. The following results were obtained: 1. Both oligodendrocytes and astrocytes in culture actively utilize acetoacetate as a precursor for lipogenesis and cholesterogenesis. 2. In both cell types, the incorporation of acetoacetate into fatty acids and cholesterol exceeds that of glucose by a factor of 5-10 when the precursors are present at concentrations of 1 mM and higher. 3. Glucose stimulates acetoacetate incorporation into fatty acids and cholesterol, whereas acetoacetate reduces the entry of glucose into these lipids. This suggests that glucose is necessary for NADPH generation, but that otherwise the two precursors contribute to the same acetyl-CoA pool. 4. Both with acetoacetate and with glucose as precursor, oligodendrocytes are more active in cholesterol synthesis than astrocytes. 5. Using incorporation of 3H2O as an indicator for total lipid synthesis, we estimated that acetoacetate contributes one third of the acetyl groups and glucose one twentieth when saturating concentrations of both substrates are present.     

A likelihood method for the detection of selection and recombination using nucleotide sequences

Different regions along nucleotide sequences are often subject to different evolutionary forces. Recombination will result in regions having different evolutionary histories, while selection can cause regions to evolve at different rates. This paper presents a statistical method based on likelihood for detecting such processes by identifying the regions which do not fit with a single phylogenetic topology and nucleotide substitution process along the entire sequence. Subsequent reanalysis of these anomalous regions may then be possible. The method is tested using simulations, and its application is demonstrated using the primate psi eta-globin pseudogene, the V3 region of the envelope gene of HIV-1, and argF sequences from Neisseria bacteria. Reanalysis of anomalous regions is shown to reveal possible immune selection in HIV-1 and recombination in Neisseria. A computer program which implements the method is available.      

Yield reduction and mycotoxin contamination of wheat due to<Emphasis Type="Italic">Fusarium culmorum</Emphasis>

The inoculation of wheat ears with 27 isolates ofFusarium culmorum in growth stage 65 reduced 1000-grain weights by 14 to 61%. For the phytopathological characterisation of isolates the virulence on primary wheat leaves and the growth rate an potato-dextrose-agar were assessed. Deoxynivalenol-producing isolates ofF. culmorum reduced the 1000-grain weight more than nivalenol-producing isolates.     

Follicular wall maintains meiotic arrest in bovine oocytes cultured in vitro

Cumulus oocyte complexes (COCs) were cocultured with parts of the follicular wall. Coculture conditions were such that the COCs were 1) in continuous contact with the follicular wall (FWC), 2) separated from the follicular wall at collection but in contact with it during culture (FWR), and 3) separated from the follicular wall, but cultured in its vicinity (FWNR). Oocytes cultured for 24 hr under FWC conditions maintained the germinal vesicle stage. Under FWR conditions the germinal vesicle stage was not maintained, but an arrest at metaphase I of meiosis occurred in mostof the oocytes. When COCs were cultured in the vicinity of the follicular wall (FWNR), meiosis was resumed and similar numbers of oocytes progressed to metaphase II of meiosis as compared to cultures of COCs without coculture with parts of the follicular wall. When COCs were isolated from the follicular wall after 24 hr of culture and additionally cultured for another 24 hr, the oocytes showed the same capability of resuming meiosis as fresh, isolated cumulus oocyte complexes. It is concluded that maintenance of contact with the follicular wall is necessary to maintain meiotic arrest. When COCs restore a physical contact with the follicular wall during culture, an arrest at metaphase I occurs. © 1994 Wiley-Liss, Inc.     

Developmental competence of bovine oocytes after specific inhibition of MPF kinase activity: effect of estradiol supplementation and follicle size

In the bovine, the concentration of 17beta-estradiol (E2) in the follicular fluid of the dominant follicle is high, indicating a possible role of E2 on the cytoplasmic maturation that occurs before the LH surge. The aim of this study was to investigate the role of E2 on the developmental competence of bovine oocytes originating from different sized follicles and temporarily maintained at the germinal vesicle stage with roscovitine (ROS). First, the efficiency of ROS to inhibit germinal vesicle breakdown (GVBD) in oocytes harvested from small (3-4 mm diameter) and medium (5-8 mm diameter) sized follicles was demonstrated. Next, the effect of E2 during temporary inhibition of GVBD by ROS on the subsequent nuclear maturation was evaluated. Oocytes from small and medium sized follicles were cultured in the presence of ROS, FSH and with or without E2 for 24 h. After this period, oocytes were cultured for another 24 h with FSH but without ROS and E2, after which the nuclear stages and the developmental competence of oocytes were assessed. In conclusion, it is demonstrated that exposure to E2, during temporary inhibition of the GVBD with ROS, affected neither nuclear nor cytoplasmic maturation of oocytes originating from small and medium sized follicles. It might be that in vivo, the increase of E2 during follicle growth is more related to selection of the dominant follicle than to the cytoplamsic maturation of the oocyte as such.