Activation of human T lymphocytes via integrin signaling induced by RGD-disintegrins

Adhesive interactions play important roles in coordinating T cell migration and activation, which are mediated by binding of integrins to RGD motif found on extracellular matrix proteins. Disintegrins, isolated from snake venoms, contain the RGD sequence that confers selectivity to integrin interaction. We have investigated the ability of three RGD-disintegrins, ligands of alpha(5)beta(1) and alpha(v)beta(3), Flavoridin (Fl), Kistrin (Kr) and Echistatin (Ech), in modulating the activation of human T lymphocyte. The disintegrins induced T cell proliferation and CD69 expression. This activation parallels with actin cytoskeleton reorganization and tyrosine phosphorylation. Furthermore, the peptides induced focal adhesion kinase (FAK) and phosphoinositide 3-kinase (PI3K) activation. Finally, RGD-disintegrins were capable of driving NF-kappaB nuclear translocation and c-Fos expression, in a PI3K and ERK1/2 activities dependent manner. This report is the first to show that RGD-disintegrins interact with integrins on human T lymphocyte surface, modulating cell proliferation and activation of specific pathways coupled to integrin receptor.     

Impact of Plant Functional Group, Plant Species, and Sampling Time on the Composition of nirK-Type Denitrifier Communities in Soil

We studied the influence of eight nonleguminous grassland plant species belonging to two functional groups (grasses and forbs) on the composition of soil denitrifier communities in experimental microcosms over two consecutive years. Denitrifier community composition was analyzed by terminal restriction fragment length polymorphism (T-RFLP) of PCR-amplified nirK gene fragments coding for the copper-containing nitrite reductase. The impact of experimental factors (plant functional group, plant species, sampling time, and interactions between them) on the structure of soil denitrifier communities (i.e., T-RFLP patterns) was analyzed by canonical correspondence analysis. While the functional group of a plant did not affect nirK-type denitrifier communities, plant species identity did influence their composition. This effect changed with sampling time, indicating community changes due to seasonal conditions and a development of the plants in the microcosms. Differences in total soil nitrogen and carbon, soil pH, and root biomass were observed at the end of the experiment. However, statistical analysis revealed that the plants affected the nirK-type denitrifier community composition directly, e.g., through root exudates. Assignment of abundant T-RFs to cloned nirK sequences from the soil and subsequent phylogenetic analysis indicated a dominance of yet-unknown nirK genotypes and of genes related to nirK from denitrifiers of the order Rhizobiales. In conclusion, individual species of nonleguminous plants directly influenced the composition of denitrifier communities in soil, but environmental conditions had additional significant effects.     

Fine needle aspiration biopsy and immunostaining findings in an aggressive inflammatory myofibroblastic tumor of the lung: a case report

BACKGROUND: Inflammatory myofibroblastic tumors (IMTs) can vary from benign pseudosarcomatous tumors to low grade sarcomas. To date, fine needle aspiration (FNA) findings of lung IMTs, especially in the aggressive form, have not been fully described. Here we present FNA biopsy findings in conjunction with immunohistochemical studies in a case of primary and recurrent pulmonary IMT. CASE: A 22-year-old man first presented with a left lung mass and 4.5 years later with a recurrent mass. Preoperative computed tomography-guided FNA was performed on both tumors. FNA cytologic smears of both specimens consisted of scant, distorted spindle cells suggestive of a spindle cell lesion but were insufficient for further classification. Needle core biopsies as well as touch imprints were performed during the FNA procedures. The imprints revealed abundant, well-preserved spindle cells with mild to moderate atypia and intermixed lymphocytes and plasma cells. The spindle cells in both specimens were immunoreactive for vimentin and smooth muscle actin and were negative for pancytokeratin, desmin, CD34 and c-kit. Thirty percent of the tumor cells were positive for p53. The findings were compatible with those of IMT. Histologic examination of the surgically resected initial and recurrent masses confirmed the diagnosis of lMT. CONCLUSION: The cytologic findings of pulmonary IMT in FNA specimens are suggestive of, although not specific for, IMT. Immunohistochemical studies can assist in the diagnosis by excluding other spindle cell lesions. Cytologic atypia and p53 immunoreactivity may be indicators of aggressive IMTs.     

X-ray absorption spectroscopic analysis of Fe(II) and Cu(II) forms of a herbicide-degrading α-ketoglutarate dioxygenase

 The first step in the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) by Ralstonia eutropha JMP134 is catalyzed by the α-ketoglutarate (α-KG)-dependent dioxygenase TfdA. Previously, EPR and ESEEM studies on inactive Cu(II)-substituted TfdA suggested a mixture of nitrogen/oxygen coordination with two imidazole-like ligands. Differences between the spectra for Cu TfdA and α-KG- and 2,4-D-treated samples were interpreted as a rearrangement of the g–tensor principal axis system. Herein, we report the use of X-ray absorption spectroscopy (XAS) to further characterize the metal coordination environment of Cu TfdA as well as that in the active, wild-type Fe(II) enzyme. The EXAFS data are interpreted in terms of four N/O ligands (two imidazole-like) in the Cu TfdA sample and six N/O ligands (one or two imidazole-like) in the Fe TfdA sample. Addition of α-KG results in no significant structural change in coordination for Cu or Fe TfdA. However, addition of 2,4-D results in a decrease in the number of imidazole ligands in both Cu and Fe TfdA. Since this change is seen both in the Fe and Cu EXAFS, loss of one histidine ligand upon 2,4-D addition best describes the phenomenon. These XAS data clearly demonstrate that changes occur in the atomic environment of the metallocenter upon substrate binding. Received: 3 July 1998 / Accepted: 13 October 1998     

Fatigue profile: a numerical method to examine fatigue in cycle ergometry

Fatigue Profile, a new numerical method for characterising fatigue in isokinetic cycle ergometry is presented and compared with the conventional fatigue index (FI). The new method describes the temporal development of muscle fatigue based on the decline of peak power output throughout a whole trial. The advantage of this method is demonstrated by the analysis of two 25 s maximum trials, separated by 90 s recovery, performed by a well-trained athlete at a pedal frequency of 120 revolutions per minute. A fourth degree polynomial was fitted to model the peak power data. Using the polynomial model coefficients the first derivative represented the rate of changing peak power which represented the Fatigue Profile. The conventional FI was calculated as -35 Ws(-1) and -32 Ws(-1) for trials 1 and 2 respectively, indicating minor differences in fatigue between trials. In contrast the Fatigue Profile revealed important numeric and temporal differences between the trials. For trial 1 a maximum rate of peak power decline of -65 Ws(-1) was reached at approximately 6 s into the trial. In marked contrast, in trial 2, maximum rate of peak power decline (-146 Ws(-1)) occurred immediately. The Fatigue Profile approach allows the characterisation of the temporal development of fatigue under different experimental conditions and in combination with other techniques may yield further insight into the underlying mechanisms of fatigue.     

pyActigraphy: Open-source python package for actigraphy data visualization and analysis

Over the past 40 years, actigraphy has been used to study rest-activity patterns in circadian rhythm and sleep research. Furthermore, considering its simplicity of use, there is a growing interest in the analysis of large population-based samples, using actigraphy. Here, we introduce pyActigraphy, a comprehensive toolbox for data visualization and analysis including multiple sleep detection algorithms and rest-activity rhythm variables. This open-source python package implements methods to read multiple data formats, quantify various properties of rest-activity rhythms, visualize sleep agendas, automatically detect rest periods and perform more advanced signal processing analyses. The development of this package aims to pave the way towards the establishment of a comprehensive open-source software suite, supported by a community of both developers and researchers, that would provide all the necessary tools for in-depth and large scale actigraphy data analyses.     

Development of restoration techniques for Hawaiian thrushes: Collection of wild eggs,artificial incubation,hand‐rearing,captive‐breeding,and re‐introduction to the wild

From 1995 to 1999, two species of endemic Hawaiian thrushes, `Oma`o (Myadestes obscurus) and Puaiohi (M. palmeri), were captive‐reared and re‐introduced into their historic range in Hawai`i by The Peregrine Fund, in collaboration with the U.S. Geological Survey–Biological Resources Division (BRD) and the Hawai`i State Department of Land and Natural Resources. This paper describes the management techniques that were developed (collection of wild eggs, artificial incubation, hand‐rearing, captive propagation, and release) with the non‐endangered surrogate species, the `Oma`o; techniques that are now being used for recovery of the endangered Puaiohi. In 1995 and 1996, 29 viable `Oma`o eggs were collected from the wild. Of 27 chicks hatched, 25 were hand‐reared and released into Pu`u Wa`awa`a Wildlife Reserve. Using the techniques developed for the `Oma`o, a captive propagation and release program was initiated in 1996 to aid the recovery of the endangered Puaiohi. Fifteen viable Puaiohi eggs were collected from the wild (1996–1997) to establish a captive breeding flock to produce birds for re‐introduction. These Puaiohi reproduced for the first time in captivity in 1998 (total Puaiohi chicks reared in captivity 1996–1998 = 41). In 1999, 14 captive‐bred Puaiohi were re‐introduced into the Alaka`i Swamp, Kaua`i. These captive‐bred birds reproduced and fledged seven chicks in the wild after release. This is the first endangered passerine recovery program using this broad spectrum of management techniques (collection of wild eggs, artificial incubation, hand‐rearing, captive‐breeding, and release) in which re‐introduced birds survived and bred in the wild. Long‐term population monitoring will be published separately [BRD, in preparation]. Zoo Biol 19:263–277, 2000. © 2000 Wiley‐Liss, Inc.     

Induction of mdr1b mRNA and P-glycoprotein expression by tumor necrosis factor alpha in primary rat hepatocyte cultures

Mammalian liver exhibits expression of members of the family of multidrug resistance (mdr) transporters (P-glycoproteins). P-glycoprotein isoforms encoded by mdr1 genes participate in extrusion of an array of xenobiotics into the bile. Induction of mdr1b mRNA expression has been shown to occur in rat hepatocytes in response to hepatotrophic growth factors. As the cytokine tumor necrosis factor alpha (TNF-α) is known to exert a direct mitogenic effect on hepatocytes, its influence on mdr1b expression was investigated. In primary rat hepatocytes cultured in the absence of TNF-α, a time-dependent increase in basal expression of mdr1b mRNA and in immunodetectable P-glycoprotein was observed. In cells treated with TNF-α (4,000 U/ml) for 3 days, expression of mdr1b mRNA and of immunodetectable P-glycoprotein was induced approximately twofold. Moreover, intracellular steady-state levels of the mdr1 substrate rhodamine 123 were decreased in cells pretreated with TNF-α in comparison to controls, indicating an increase in functional transporter(s) mediating dye extrusion. Treatment of hepatocytes with antioxidants (1 mM ascorbic acid and 2% dimethyl sulfoxide) for 3 days markedly suppressed mdr1b mRNA and P-glycoprotein expression both in cells cultured in the presence of TNF-α and in the absence of the cytokine, but did not fully abolish mdr1b mRNA induction by TNF-α, supporting the notion that reactive oxygen species participate in regulation of basal mdr1b gene expression during hepatocyte culture. In conclusion, the present data indicate that by inducing mdr1b expression in hepatocytes, TNF-α may affect the capacity of the liver for extrusion or detoxification of endogenous or xenobiotic mdr1 substrates. J. Cell. Physiol. 176:506–515, 1998. © 1998 Wiley-Liss, Inc.