Machine learning based longitudinal virtual diagnostics at SwissFEL.

The bunch length in a linac driven Free Electron Laser (FEL) is a major parameter to be characterized to optimize the final accelerator performance. In linear machines, this observable is typically determined from the beam imaged on a screen located downstream of a Transverse Deflecting Structure (TDS) used to impinge a time dependent kick along the longitudinal coordinate of the beam. This measurement is typically performed during the machine setup and only sporadically to check the beam duration, but it cannot be continuously repeated because it is time consuming and invasive. A non-invasive method to determine the electron bunch length has already been presented in the past. This method is based on the analysis of the synchrotron radiation light spot emitted by the bunch passing through a magnetic chicane, provided that the energy chirp impinged on the bunch by the upstream radio frequency structures is known. In order to overcome a systematic discrepancy affecting the synchrotron radiation monitor based results compared to the absolute TDS based ones, we implemented and optimized a machine learning approach to predict the bunch length downstream of the two SwissFEL compression stages-from about 10 fs up to about 2 ps-as well as the beam longitudinal profile at the first one.

Generation and Characterization of Intense Ultralow-Emittance Electron Beams for Compact X-Ray Free-Electron Lasers.

The transverse emittance of the electron beam is a fundamental parameter in linac-based x-ray free-electron lasers (FELs). We present results of emittance measurements carried out at SwissFEL, a compact x-ray FEL facility at the Paul Scherrer Institute in Switzerland, including a description of the novel high-resolution measurement techniques and the optimization procedure. We obtained slice emittance values at the undulator entrance down to 200 nm for an electron beam with a charge of 200 pC and an rms duration of 30-40 fs. Furthermore, we achieved slice emittances as low as 100 nm for 10 pC beams with few fs duration. These values set new standards for electron linear accelerators. The quality, verification, and control of our electron beams allowed us to generate high-power FEL radiation for a wavelength as short as 0.1 nm using an electron beam with an energy of only 6 GeV. The emittance values demonstrated at SwissFEL would allow producing hard x-ray FEL pulses with even lower-energy beams, thus paving the way for even more compact and cost-effective FEL facilities.

Passive Linearization of the Magnetic Bunch Compression Using Self-Induced Fields.

In linac-driven free-electron lasers, colliders, and energy recovery linacs, a common way to compress the electron bunch to kiloampere level is based upon the implementation of a magnetic dispersive element that converts particle energy deviation into a path-length difference. Nonlinearities of such a process are usually compensated by enabling a high harmonic rf structure properly tuned in amplitude and phase. This approach is however not straightforward, e.g., in C-band and X-band linacs. In this Letter we demonstrate that the longitudinal self-induced field excited by the electron beam itself is able to linearize the compression process without any use of high harmonic rf structure. The method is implemented at the FERMI linac, with the resulting high quality beam used to drive the seeded free-electron laser during user experiments.

The Brazilian Peritoneal Dialysis Multicenter Study (BRAZPD) : characterization of the cohort.

The Brazilian Peritoneal Dialysis Multicenter Study (BRAZPD) was launched in December 2004 aiming to collect data monthly and continuously from a representative cohort, allowing for a continuous snapshot of the peritoneal dialysis (PD) reality in the country. This is an observational study of PD patients comprising follow-up from December 2004 to February 2007 (mean follow-up of 13.6 months-ranging from 1 to 26 months) in 114 Brazilian centers. All centers report data through a central web-based database. After an initial baseline retrospective data collection, all patients are followed prospectively every month until they drop out from the PD program. Total number of patients recruited until February 2007 was 3226 (2094 incident patients). Mean age was 54+/-19 years (37% above 65 years old), with 55% females and 64% Caucasians. The more frequent causes of renal failure were diabetic nephropathy (34%), renal vascular disease associated with hypertension (26%), and glomerulopathies (13%). The most common comorbidities were hypertension (76%), diabetes (36%), and ischemic heart disease (23%). Automated PD (APD) was the modality utilized in 53%. The estimated overall peritonitis rate was 1 episode per 30 patient-months (most frequently due to Staphylococcus aureus). The total dropout rate was 33%, mainly due to deaths, whereas 20% of dropouts were due to renal transplant. The gross mortality was 17.6% and the main causes of mortality were cardiovascular diseases (40%) and infections (15%). The initial results of this first Brazilian PD registry provide a unique opportunity to develop future clinical studies addressing specific PD questions in the Brazilian reality and context.

[Resistance of intensive care unit nurses to caring for conscious patients]. / Pesquisando a existência de resistência por parte da equipe de enfermagem do CTI em assistir pacientes conscientes.

The authors believe that intensive Care Units (ICU) is a very stressful place for both patients and workers. They associate the success of the treatment to the relationship between these two groups. This article intends to investigate the existence of resistance among nursing personnel in assisting conscious patient in ICU. The date were analyzed through the "content analysis" proposed by Bardin (1979) and through the methodology utilized by Magaihäes (1991).

Establishment and characterization of a new granulocyte-macrophage colony-stimulating factor-dependent and interleukin-3-dependent human acute myeloid leukemia cell line (GF-D8).

A novel factor-dependent human myeloid leukemia cell line (GF-D8) was established from the peripheral blood of an 82-year-old man suffering from acute myeloblastic leukemia (AML). By morphology, cytochemical staining, and analysis of surface antigens, GF-D8 cells are myeloblasts of immature progenitor origin. The consensus karyotype is 45, XY, -5, 7q-, inv(7) (q31.2q36), 8q+, +8q+, 11q+, 12p-, -15, -17, + marker. The long-term survival and proliferation of GF-D8 cells is dependent on the presence of either granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-3 (IL-3). Weak colony growth was observed after exposure of GF-D8 cells to stem cell factor (SCF) but not after exposure to granulocyte-CSF (G-CSF), macrophage-CSF (M-CSF), IL-1 beta, IL-2, IL-5, or tumor necrosis factor-alpha (TNF-alpha). GM-CSF- and IL-3-induced proliferation is dose dependent, with significant growth observed at concentrations as low as 0.1 ng/mL, but the combination of both factors has no synergistic effect. A significant proliferation is induced by GM-CSF and IL-3 even in serum-deprived cultures, although with a slightly decreased efficiency. GF-D8 cells were shown to express specific messenger RNAs for the alpha chains of the GM-CSF and IL-3 receptors as well as for the beta chain, common to both receptors. Interestingly, despite the absence of biologic response to G-CSF, specific transcripts for the G-CSF receptor gene were similarly identified by reverse polymerase chain reaction analysis. GF-D8 cells represent a useful tool for studying chromosome abnormalities of human AML as well as the regulation of myeloid proliferation and differentiation in vitro.

Transcriptional and post-transcriptional regulation of IL-1 beta, IL-6 and TNF-alpha genes in chronic lymphocytic leukaemia.

The present study was designed to define the mechanisms of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumour necrosis factor (TNF-alpha) gene regulation in chronic lymphocytic leukaemia of B cell origin (B-CLL). By nuclear run-on analysis, all B-CLL cases displayed high levels of nuclear transcription of the IL-6 and TNF-alpha genes, whereas IL-1 beta gene transcription was only barely detectable. Upon in vitro culture for 1 h, B-CLL cells from different patients were substantially heterogeneous in terms of expression of steady state mRNA levels of IL-1 beta, IL-6 and TNF-alpha even though the pattern of nuclear transcription of these cytokines was only marginally affected by in vitro culture. mRNA stability was then examined and cytokine gene transcripts showed a half life of more than 2 h in cultured B-CLL cells and treatment with cycloheximide (CHX) did not affect cytokine transcript levels in B-CLL cells. These results indicate that: steady state levels of each mRNA do not reflect the rate of nuclear transcription of these cytokines in fresh or cultured B-CLL cells, that purification and in vitro culture of leukaemic cells may amplify cytokine gene expression in B-CLL, and that cytokine gene transcripts are relatively stable in B-CLL.

Interleukin-1 regulates cytokine gene expression in human mesangial cells through the interleukin-1 receptor type 1.

We have recently shown that interleukin-1 is a potent stimulus of gene expression and production of leukocyte chemotactic factors, colony-stimulating factors, and interleukin-6 in human mesangial cells in culture. Here, we sought to determine whether interleukin-1 induces its own gene expression in human mesangial cells. Interleukin-1 mRNA levels were quantitated by Northern blot analysis with total cellular RNAs isolated from human mesangial cells exposed for 6 h to medium alone or in the presence of human recombinant interleukin-1 beta (1 to 100 ng/mL). Interleukin-1 induced interleukin-1 mRNA expression in a dose-dependent manner. An additional finding of this study was that human mesangial cells constitutively express the 80 kd interleukin-1 receptor type 1 gene. When human mesangial cells were exposed to interleukin-1, interleukin-1 receptor expression was not modified. Similarly, other stimuli like tumor necrosis factor, transforming growth factor beta, or interleukin-6 did not modulate interleukin-1 receptor expression. Recombinant interleukin-1 receptor antagonist blocked the interleukin-1 mRNA as well as interleukin-6 and interleukin-8 mRNA accumulation induced by interleukin-1 beta. Lipopolysaccharide, which is a known stimulus for interleukin-1 transcription in several cell types, also induced interleukin-1 mRNA accumulation, thus indicating that lipopolysaccharide mediates interleukin-1 gene activation in human mesangial cells through an interleukin-1-independent pathway. These data support the pivotal role of interleukin-1 in regulating mesangial cell cytokine genes and may be taken to indicate the existence of an interleukin-1-mediated positive feedback loop that might control the secretion of active cytokines within the glomeruli when an immunological or inflammatory injury takes place.

Constitutive expression of IL-1 beta, M-CSF and c-fms during the myeloid blastic phase of chronic myelogenous leukaemia.

During the myeloid blast crisis (BC) of chronic myelogenous leukaemia (CML) non-random additional chromosome abnormalities occur in over 80% of patients. However, these cytogenetic changes have been reported to precede the clinical signs of CML-BC by several months to years suggesting that other biological events may participate in the multistep process of acute transformation of CML. The autocrine production of growth factors has been recently shown to occur in several haematological malignancies and particularly in acute myeloblastic leukaemia (AML). In the present report we demonstrate that IL-1 beta gene is expressed in almost all cases of CML in myeloid blast crisis. The secretion of IL-1 from CML blasts in culture supernatants was confirmed in all five of the patients we studied. A high proportion of cases showed constitutive expression of the M-CSF gene and many of the same patients often had a simultaneous co-expression of the proto-oncogene c-fms which encodes for the M-CSF receptor. After exposure of leukaemic cells to phorbol myristate acetate (PMA), release of M-CSF protein was documented in three of five patients studied. No significant interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) or granulocyte colony-stimulating factor (G-CSF), was detected in these patients demonstrating that a different pattern of growth factors secretion exist in AML and CML, where distinct molecular events are likely involved in the control of leukaemic proliferation.

Modulation of cell proliferation and cytokine production in acute myeloblastic leukemia by interleukin-1 receptor antagonist and lack of its expression by leukemic cells.

Interleukin-1 (IL-1) is spontaneously produced by acute myeloblastic leukemia (AML) cells. IL-1 also induces synthesis of colony-stimulating factors (CSFs) and sustains leukemic growth. An IL-1-specific inhibitor has been recently purified and cloned; this molecule binds to IL-1 receptors but has no IL-1 activity, fulfilling the characteristics of an IL-1 receptor antagonist (IL-1ra). Because high-affinity binding sites for IL-1ra were shown on AML cells by radioligand binding studies, we studied the effect of IL-1ra on the proliferative activity of blast cells isolated from 16 cases of AML. In each case, spontaneous proliferation was inhibited by addition of the IL-1ra in a dose-dependent manner (1 to 100 ng/mL). Culture supernatants of unstimulated leukemic cells contained IL-1 beta and granulocyte-macrophage CSF (GM-CSF), but when incubated with the IL-1ra, a reduction or disappearance of GM-CSF was observed in 8 of 10 cases, whereas spontaneous IL-1 production was reduced in four of seven cases. By Northern hybridization, IL-1 beta gene transcripts were shown in 20 of 23 AML cases, whereas IL-1ra-specific messenger RNA was present in only two of the patients studied. These data show a role for IL-1 in the spontaneous proliferation and cytokine production of AML cells and suggest that an imbalanced synthesis of IL-1 and of its natural receptor antagonist may contribute to the unrestricted growth of AML cells.

Interleukin-1 beta and tumor necrosis factor-alpha induce gene expression and production of leukocyte chemotactic factors, colony-stimulating factors, and interleukin-6 in human mesangial cells.

The capacity of human cultured mesangial cells to produce soluble factors potentially relevant for mechanisms of inflammation and immunity at the glomerular site was analyzed. The nature of the secreted factors initially was investigated by Northern blot analysis using total cellular RNAs isolated from resting and activated mesangial cells. On exposure of mesangial cells to human recombinant interleukin-1 beta (IL-1 beta), high levels of interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) mRNAs were detected. Similar transcripts were found after stimulation with human recombinant tumor necrosis factor-alpha (TNF-alpha). Active secretion of IL-8 was documented by radioimmunoassay in supernatants of mesangial cells activated by either IL-1 beta or TNF-alpha. Using an in vitro migration assay, supernatants from resting mesangial cells were found to be devoid of any chemotactic activity for granulocytes or monocytes. On stimulation with IL-1 beta, however, mesangial cell supernatants expressed MCP-1 biologic activity detected as induction of a strong migratory response for human monocytes but not for granulocytes. In addition, IL-1 beta and TNF-alpha induced high levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF) mRNAs. Similarly IL-1 beta and TNF-alpha induced the interleukin-6 (IL-6) gene and active secretion of its mature protein. These data strongly support an effector role for mesangial cells in modulating immune-inflammatory responses in glomeruli. Release of cytokines may activate not only infiltrating inflammatory cells through short paracrine pathways, but also mesangial cells themselves through an autocrine pathway.

Expression of leukocyte alkaline phosphatase gene in normal and leukemic cells: regulation of the transcript by granulocyte colony-stimulating factor.

The levels of leukocyte alkaline phosphatase (LAP) messenger RNA (mRNA) are evaluated in B and T lymphocytes, monocytes, and polymorphonuclear cells (PMNs), and this transcript is found to be present only in PMNs. Precursors of the myelomonocytic pathway, represented by leukemic cells isolated from several cases of chronic myelogenous leukemia (CML) in its stable and blastic phase and acute myelogenous leukemia (AML), are devoid of LAP transcript. These data support the notion that LAP is a marker of the granulocyte terminal differentiation. Despite the absence of LAP mRNA in both the myeloid and the lymphoid precursors, nuclear run-on experiments show constitutive transcription of the LAP gene in leukemic cells obtained from AML, CML, as well as acute lymphoblastic leukemia (ALL) and B-cell chronic lymphocytic leukemia (B-CLL). In CML and in chronic myelo-monocytic leukemia (CMML) PMNs, granulocyte colony-stimulating factor (G-CSF) specifically accumulates LAP mRNA without showing a substantial increase in the rate of transcription of the LAP gene. Once increased by G-CSF, LAP mRNA is very stable, showing a half-life of more than 4 hours in the presence of actinomycin-D. G-CSF is suggested to play a pivotal role in the modulation of LAP transcript in PMNs.

Interleukin-1 and interleukin-2 control granulocyte- and granulocyte-macrophage colony-stimulating factor gene expression and cell proliferation in cultured acute myeloblastic leukemia.

In vitro proliferation of leukemic cells purified from 10 cases of acute myeloblastic leukemia (AML) was analyzed in basal conditions or in the presence of exogenous recombinant (r) Interleukin (IL) 1. In parallel, blasts from 5 of these patients were studied for granulocyte-macrophage colony-stimulating factor (GM-CSF) or granulocyte-CSF (G-CSF) mRNA. IL-1 augmented the spontaneous AML cell proliferation in all cases and induced de novo expression or increased amounts of GM-CSF and/or G-CSF transcripts in 4 of the 5 cases evaluated. IL-1-induced AML cell proliferation was modulated by neutralizing anti-GM-CSF or anti-G-CSF antibodies in those cases in which CSF mRNAs were induced or increased by exogenous cytokine. In the same cases, biosynthetic labelling and immunoprecipitation studies using monospecific anti-GM-CSF antibodies showed that IL-1 also increased the levels of GM-CSF protein synthesis. Addition of neutralizing anti-IL-1 antibodies to AML cell cultures completely abolished ongoing GM-CSF synthesis, suggesting that endogenous IL-1 is needed to maintain autocrine production of CSFs. The effects of rIL-2 were investigated in a larger series of 21 patients. The cytokine reduced spontaneous AML cell proliferation in 8 cases. It caused complete disappearance of GM-CSF mRNA in 1 case, and marked reduction of G-CSF mRNA in 2 cases. Increased AML cell proliferation was observed in 2 of 21 cases. These findings suggest that expression of CSF genes and cell proliferation in AML are under the control of different cytokines acting in autocrine or paracrine fashion.

Constitutive expression of the interleukin-6 gene in chronic lymphocytic leukemia.

Interleukin-6 (IL-6) is a pleiotropic lymphokine active as a growth factor on B-cell hybridomas and plasmacytomas and found to be identical with B-cell stimulatory factor 2, interferon beta 2, 26-Kd protein, and hepatocytes stimulating factor. IL-6 gene expression was investigated in fresh human chronic lymphocytic leukemia (B-CLL) and in acute lymphoblastic leukemia (ALL) by Northern blot analysis using a specific cDNA probe. 1.3-kb IL-6 transcript was found in six out of 11 B-CLL patients, while no hybridization was observed in ten cases of ALL of both T- and B-cell origin. The constitutive expression of IL-6 transcripts was associated with production of a biologically active protein as determined by using the IL-6-dependent 7TD1 cell line. It remains to be elucidated whether IL-6 gene expression is indeed important in the regulation of B-CLL growth or in its clinical manifestation.

Differences in the expression of alkaline phosphatase mRNA in chronic myelogenous leukemia and paroxysmal nocturnal hemoglobinuria polymorphonuclear leukocytes.

Paroxysmal nocturnal hemoglobinuria (PNH) and the stable phase of chronic myelogenous leukemia (CML) are the two hematological conditions known to be associated with low levels of leukocyte alkaline phosphatase (LAP) activity in peripheral blood polymorphonuclear cells (PMN). LAP mRNA levels were determined in PMN from PNH and CML patients by RNA blotting analysis. In CML, LAP mRNA is undetectable, suggesting either decreased transcription or rapid degradation of the message. Contrarily, in PNH normal or high levels of LAP mRNA are present. This latter finding supports the concept of a deficit in the anchorage of the protein to the plasma membrane through the glycolipid pathway, even though other post-transcriptional mechanisms could be involved.