Single Shot Characterization of High Transformer Ratio Wakefields in Nonlinear Plasma Acceleration.

Plasma wakefields can enable very high accelerating gradients for frontier high energy particle accelerators, in excess of 10 GeV/m. To overcome limits on single stage acceleration, specially shaped drive beams can be used in both linear and nonlinear plasma wakefield accelerators (PWFA), to increase the transformer ratio, implying that the drive beam deceleration is minimized relative to acceleration obtained in the wake. In this Letter, we report the results of a nonlinear PWFA, high transformer ratio experiment using high-charge, longitudinally asymmetric drive beams in a plasma cell. An emittance exchange process is used to generate variable drive current profiles, in conjunction with a long (multiple plasma wavelength) witness beam. The witness beam is energy modulated by the wakefield, yielding a response that contains detailed spectral information in a single-shot measurement. Using these methods, we generate a variety of beam profiles and characterize the wakefields, directly observing transformer ratios up to R=7.8. Furthermore, a spectrally based reconstruction technique, validated by 3D particle-in-cell simulations, is introduced to obtain the drive beam current profile from the decelerating wake data.

Comparative hospital economics and patient presentation: vertebroplasty and kyphoplasty for the treatment of vertebral compression fracture.

BACKGROUND AND PURPOSE: Previous studies evaluating vertebral augmentation procedure costs have not made detailed comparisons between vertebroplasty and kyphoplasty. Our study contrasts hospital costs for vertebroplasty versus kyphoplasty for the treatment of vertebral compression fractures in routine clinical practice in the United States. MATERIALS AND METHODS: This retrospective cohort study analyzed 2007-2008 hospital discharge and billing records from the Premier Perspective data base. The primary outcome variable, differences in total hospital cost between vertebroplasty and kyphoplasty, was assessed by using analysis of covariance. RESULTS: Three thousand six hundred seventeen patients received vertebroplasty (64% inpatient, 36% outpatient), and 8118 received kyphoplasty (54% inpatient, 46% outpatient). Approximately 75% were women, and most were white. Mean total unadjusted inpatient costs were $9837 for vertebroplasty versus $13 187 for kyphoplasty (P < .0001). Outpatient vertebroplasty costs were $3319 versus $8100 for kyphoplasty (P < .0001). Lower vertebroplasty costs were largely due to differences in hospital supply and OR. Mean vertebroplasty OR costs were $73.60 (anesthesia), $112.06 (recovery room), and $990.12 (surgery) versus $172.16 (anesthesia), $257.47 (recovery room), and $1,471.49 (surgery) with kyphoplasty. Adjustments for age, sex, admission status, and disease severity accentuated the differences. Mean adjusted inpatient costs were $11 386 for vertebroplasty versus $16 182 for kyphoplasty (P < .0001), and outpatient costs were $2997 for vertebroplasty versus $7010 for kyphoplasty (P < .0001). After adjustments for the same covariates, length-of-stay differences were no longer evident (P = .4945). CONCLUSIONS: Performing vertebroplasty versus kyphoplasty reduces hospital costs by nearly $5000 for inpatient procedures and by more than $4000 for outpatient procedures.

Arthrographic joint distension with saline and steroid improves function and reduces pain in patients with painful stiff shoulder: results of a randomised, double blind, placebo controlled trial.

OBJECTIVE: To determine whether arthrographic distension with a mixture of saline and steroid, in patients with painful stiff shoulder for at least 3 months, is better than placebo in improving function, pain, and range of motion at 3, 6, and 12 weeks. METHODS: A randomised, placebo controlled trial with participant and outcome assessor blinding in which shoulder joint distension with normal saline and corticosteroid was compared with placebo (arthrogram). Outcome measures, assessed at 3, 6, and 12 weeks, included a shoulder-specific disability measure (SPADI), a patient preference measure (Problem Elicitation Technique (PET)), pain, and range of active motion. RESULTS: From 96 potential participants, 48 were recruited. Four withdrew from the placebo group after the 3 week assessment and three subsequently received arthrographic distension with saline and steroid. At 3 weeks, significantly greater improvement in SPADI (p = 0.005), PET, overall pain, active total shoulder abduction, and hand behind back was found in participants in the joint distension and steroid group than in the placebo group. At 6 weeks the results of the intention to treat analysis favoured joint distension, although the between-group differences were only significant for improvement in PET (difference in mean change in PET between groups = 45.9 (95% CI 3.2 to 88.7). Excluding the four withdrawals, the between-group differences for the disability and pain measures significantly favoured distension over placebo. At 12 weeks, both the intention to treat analysis and an analysis excluding the four withdrawals demonstrated a significantly greater improvement in PET score for the distension group. CONCLUSIONS: Short term efficacy of arthrographic distension with normal saline and corticosteroid over placebo was demonstrated in patients with painful stiff shoulder.

Cell counting.

This unit presents protocols for counting cells using either a hemacytometer or electronically using a Coulter counter. Cell counting with a hemacytometer permits effective discrimination of live from dead cells using trypan blue exclusion. In addition, the procedure is less subject to errors arising from cell clumping or size heterogeneity. Counting cells is more quickly and easily performed using an electronic counter, but live-dead discrimination is unreliable. Cell populations containing large numbers of dead cells and/or cell clumps are difficult to count accurately. In addition, electronic counting requires resetting of the instrument for cell populations of different sizes; heterogeneous populations can give rise to inaccurate counts, and resting and activated cells may require counting at separate settings. In general, electronic cell counting is best performed on fresh peripheral blood cells.

Defects in intracellular oxidative metabolism of neutrophils undergoing apoptosis.

Apoptosis permits neutrophil recognition by macrophages, thereby not only limiting potential cytotoxicity but also promoting resolution of inflammation. A direct relationship between apoptosis and intracellular hydrogen peroxide (H2O2) production was observed in phorbol 12-myristate 13-acetate (PMA) -stimulated neutrophils aged in culture. A significant decrease in intracellular H2O2 production was observed in aging neutrophils at 12, 24, and 48 h. However, intracellular superoxide anion production in response to PMA stimulation was preserved up to 24 h, implying retention of intracellular signaling pathways leading to NADPH oxidase stimulation. A significant decrease in the cytoplasmic content and activity of Cu,Zn superoxide dismutase was responsible for the observed decline in intracellular H2O2 production in apoptotic neutrophils. Intracellular glutathione content also decreased concomitantly with H2O2 production. These observations indicate that onset of apoptosis in neutrophils is in part mediated by oxidative stress resulting from the down-regulation of key antioxidant defense systems of the cell, namely superoxide dismutase and glutathione.

Application of contrast agents in the evaluation of stroke: conventional MR and echo-planar MR imaging.

The availability of new therapeutic interventions, including neuroprotective agents and endovascular thrombolysis, has given new hope to patients suffering an acute stroke. Early intervention remains a key factor in the effectiveness of these new and traditional treatments. More importantly, the capability to assess the viability and reversibility of the ischemic tissue became essential for better delineation and differentiation of infarcted versus ischemic tissue and patient management. Abnormal MR imaging (MRI) findings during acute stroke usually reflect the underlying pathophysiologic changes, which can be classified into three sequential stages: (a) hypoperfusion, (b) cellular dysfunction and (c) breakdown of the blood-brain barrier. The first stage is a kinetic phenomenon (not biologic) and, therefore, can be detected immediately. Contrast agents accentuate the abnormal flow kinetics and facilitate the early diagnosis of ischemia using either conventional MRI or newly developed echo-planar perfusion imaging (EPPI). The demonstration of abnormal arterial or parenchymal enhancement on conventional MRI during acute stroke provides the earliest sign of vascular occlusion/stenosis. EPPI, in contrast, provides information related to microcirculation (< 100 microns) and tissue reserve (cerebral blood volume) that cannot be obtained by conventional angiography and is directly related to the target end-organ. Further information obtained from both contrast MRI and EPPI may have a predictive value in the clinical outcome of acute stroke patients.

Rapid multivariate analysis and display of cross-reacting antibodies on human leukocytes.

We present an application which can rapidly determine the binding patterns of monoclonal antibodies on mixed populations of cells simultaneously in a single rapid analysis. It is an application of the tube identifier parameter (TIP) system which can provide fully correlated list-mode data of the entire patient phenotype in a single file. Using the phenogram analytical display, we are able to determine the cross-reacting antibodies for an entire antibody panel for each cell type. This information can be displayed in a single plot. Using light scatter gating to select different populations of lymphocytes, monocytes, and neutrophils, phenograms can be simultaneously generated. This provides a directly comparable means of displaying the positive and negative binding characteristics of each antibody on each cell population. Any marker combination that is abnormal will be identifiable in the phenogram. Additionally, by plotting the fluorescence distributions of each marker beside one another (termed overview), quantifiable differences in intensity can be determined. There are 3 major benefits of the proposed analysis. By using the TIP concept, several sets of antibodies can be compared simultaneously. Any light scatter gate can be used and this gate can be changed on one histogram or plot, yet apply to the total analysis. Data analysis is particularly rapid since the entire phenotype of a patient can be evaluated by performing a single rapid analysis.

Time interval gating for analysis of cell function using flow cytometry.

We propose a method which significantly shortens the time required for both the collection and analysis of data derived from multiple sample, flow cytometric kinetic assays. We have defined the term Time Interval Gating (TIG) to describe this method. TIG effectively allows one flow cytometer to concurrently monitor several samples over the course of a kinetic assay. Data for all samples are stored in a single FCS 2.0 compatible listmode data file which we refer to as the TIG data file. TIG is adaptable to most commerical flow cytometers. Standard listmode analysis software can be used to analyze the TIG data files and correlate any combination of tubes and/or time intervals from the assay. Results for the entire assay can be displayed on a single two parameter plot. This paper describes how TIG is applied to neutrophil oxidative burst measurement using a standard EPICS Elite flow cytometer. In this assay, 11 samples were each monitored for 30 min to identify the extent to which volatile organic chemicals (VOCs) inhibited the oxidation of DCFH in stimulated neutrophils. TIG makes the oxidative burst assay practical for high volume screening by reducing the overall flow cytometer and analysis time required by a factor of ten. In addition, TIG provides an organized approach to managing data acquisition on instruments equipped with automated sampling systems.

An autoradiographic study of the uptake and distribution of iron by the brain of the young rat.

Rats aged 15, 28, or 42 days were injected intraperitoneally with iron-59 and were sacrificed at varying intervals. Total acquisition of iron-59 by the brain, when compared to levels of iron-59 in blood sampled 48 h after injection, diminished with increasing age at injection. Cerebral levels of iron-59 in animals injected at age 15 days did not change with postinjection interval despite rapidly decreasing serum levels of iron-59. Thus, iron acquired by the brain early in postnatal development becomes sequestered in that organ. However, autoradiography of the brains of animals injected at age 15 days showed definite changes over time in the anatomic distribution of the isotope. This suggests that mechanisms may exist for the translocation of iron from one area of the brain to another.

Effect of cytoskeletal geometry on intracellular diffusion.

A method is presented for determining the retardation of diffusion of particles inside cells owing to cytoskeletal barriers. The cytoskeletal meshwork is treated as a repeating periodic two-dimensional or three-dimensional lattice composed of elements of given size, shape, and spacing. We derive an analytic expression for the diffusion coefficient relative to that of the cytosol. This expression is evaluated by solving numerically an appropriate boundary-value problem for the Laplace equation. For the two-dimensional case, e.g., diffusion in a membrane, the results are quantitatively similar to those obtained by Saxton (1987. Biophys. J. 52:989-997) using Monte Carlo methods. The three-dimensional results are quantitatively similar to experimental results reported by Luby-Phelps et al. (1987. Proc. Natl. Acad. Sci. USA. 84:4910-4913) for the diffusion of dextran and Ficoll particles in Swiss 3T3 cells. By accounting for geometrical factors, these results allow one to assess the relative contributions of geometrical hindrance and of binding to the cytoskeletal lattice from measurements of intracellular diffusion coefficients of proteins.

Cerebral toxoplasmosis and lymphoma in patients with acquired immunodeficiency syndrome.

16 Patients with central nervous system (CNS) complications of the acquired immunodeficiency syndrome (AIDS) are described. All patients were male homosexuals. The most common demonstrable lesion in the parenchyma was toxoplasmosis, which produced an area of focal oedema, usually containing a central zone of nodular or ring-shaped enhancement. Cerebral atrophy was also a common finding. One patient had diffuse peri-ventricular lymphomatous infiltration, and a further two patients had both cerebral toxoplasmosis and lymphoma. A delayed "double dose" contrast examination appears to be the most accurate method of outlining the total extent of CNS disease in these patients.

A comparison of changes seen on radiographs of rheumatoid arthritis patients in Australia and in China.

To test the hypothesis that rheumatoid arthritis in patients in China is milder in severity than that in patients in a western country, a comparison was made of 2 series of consecutive outpatients with definite or classic rheumatoid arthritis who were attending referral centers in Melbourne, Australia and Shanghai, China. This paper reports the findings on radiographs of the wrists and hands. Making allowances for age and duration of disease, changes were more frequent and severe in the Australian patient series, particularly at the metacarpophalangeal joints.

Nutritional status of middle-aged and elderly females in Kentucky in two seasons: Part 1. Body weight and related factors.

Middle-aged and elderly females aged between 51 and 86 years volunteered for this study. In June and July, 147 females were studied; data collected through interview included general socioeconomic information, health history, use of medication, and a 7-day food intake. During the same 7-day period, physical activity level was measured for each person by use of a pedometer. On the 8th day, anthropometric measurements were conducted and fasting blood was analyzed for certain hormones and related metabolites. In the following January and February, the same group was surveyed again and the same measurements were repeated. Of the initial 147 subjects, 130 persons completed the winter survey. A comparison of the summer and winter data indicated some significant differences: mean body weight increased in winter from 70.4 +/- 12.7 to 71.1 +/- 13.5 kg (p less than or equal to 0.05); energy intake was raised from 1450 +/- 384 to 1549 +/- 372 kcal (p less than or equal to 0.01); physical activity decreased from 10.9 +/- 8.2 to 8.5 +/- 5.4 miles/week (p less than or equal to 0.01); and serum free thyroxine (T4) fell from 1.72 +/- 0.27 to 1.64 +/- 0.27 ng/dl. These results together with other data suggest that more attention should be addressed to seasonal fluctuations involved in body weight maintenance.

Nutritional status of middle-aged and elderly females in Kentucky in two seasons: Part 2. Hematological parameters.

There is some indication that change of seasons, from summer to winter, alters certain hematological parameters that could be indicative of hemodilution and hemoconcentration. To investigate this further, we studied adult females (n = 130) aged between 51 and 86 years during summer and winter to evaluate any seasonal variations in selected hematological and related parameters. Data included a 7-day food intake, anthropometry, and hematological analysis of fasting blood. Erythrocyte and leukocyte counts, hematocrit (HCT), and hemoglobin (Hb) increased significantly in the winter compared to summer (p less than 0.01), but intakes of folacin, vitamin B12, and iron did not change. No effects of age or race were observed on these changes. Significantly elevated leukocyte counts (p less than 0.002), HCT (p less than 0.03), and Hb (p less than 0.007) were observed among smokers; however, smoking had no effect on the seasonal changes in hematological values. The increase in HCT was greater for persons using diuretics than those who were not on diuretics (p less than 0.05). The seasonal changes in erythrocyte counts (p less than 0.01), HCT (p less than 0.01), and Hb (p less than 0.05) were significantly correlated to the changes in plasma protein concentration among the subjects, suggesting hemoconcentration in winter and hemodilution in summer to some extent. The present study suggests that seasonal variation may occur in hematological parameters and that these factors should be taken into consideration when evaluating survey data.

A comparison of rheumatoid arthritis in Australia and China.

A comparison was made of two series of consecutive outpatients with a presumptive diagnosis of rheumatoid arthritis (RA) attending referral centres in Melbourne and Shanghai. No significant differences were observed in disease onset, course, presence of antinuclear antibodies (ANA), or seropositivity. In the Australian series there was a higher frequency of nodules, Raynaud's phenomenon, carpal tunnel syndrome, and 'classical' in comparison with 'definite' disease, and a lower frequency of lymphadenopathy and hepatomegaly. Joint tenderness and soft tissue swelling tended to be more marked in the Chinese series, while deformity and limited range of movement were less severe. Drug therapy was similar overall but influenced by drug availability. Peptic ulceration was recorded in 28% of the Australian series but in only 6% of the Chinese; although 25% of the Chinese were receiving antacids and 6% antiulcerants. X-rays of hands and feet showed more severe disease in the Australian series. The older age group and longer duration of the disease in the Australian patients, who had more chronic and less active disease, may have influenced some of these results.

Intravenous digital subtraction angiography in patients with carotid territory ischemia: a prospective trial.

To evaluate the place of intravenous digital subtraction angiography (IV-DSA) in the investigation of patients with carotid territory ischemia, we have compared the IV-DSA and conventional angiographic (CA) findings in 40 patients in a prospective study. Arterial disease was assessed by grading stenosis from zero (normal artery) to six (complete occlusion) and recording any luminal ulceration. In 59 of 66 bifurcations imaged by both techniques, the IV-DSA evaluation of any internal carotid artery origin disease was within one grade of the CA assessment, with three false negatives and four false positives. Luminal ulceration was less reliably predicted, and two clinically important middle cerebral artery lesions were missed by IV-DSA. In 11 patients who had carotid endarterectomy, there was a good correlation between surgical, CA, and IV-DSA findings, although some ulcerations were not detected by either angiographic technique. These results suggest that IV-DSA is a sensitive technique for detection of carotid bifurcation stenosis when the study is of good quality, but that intracranial lesions may be missed.

Acute median nerve compression by haemorrhage from acute myelomonocytic leukaemia.

A 61-year-old male receiving treatment for acute myelomonocytic leukaemia (AMML) developed weakness and sensory loss in the thumb, index and middle finger and half of the ring finger of the left hand as a result of a spontaneous haemorrhage into the carpal tunnel and forearm, an unusual cause of median nerve compression. These findings were confirmed by CT scanning and post-mortem examination. This is the first report of spontaneous haemorrhage occurring in a patient with AMML.