Novel Measurement of the Neutron Magnetic Form Factor from A=3 Mirror Nuclei

The electromagnetic form factors of the proton and neutron encode information on the spatial structure of their charge and magnetization distributions. While measurements of the proton are relatively straightforward, the lack of a free neutron target makes measurements of the neutron's electromagnetic structure more challenging and more sensitive to experimental or model-dependent uncertainties. Various experiments have attempted to extract the neutron form factors from scattering from the neutron in deuterium, with different techniques providing different, and sometimes large, systematic uncertainties. We present results from a novel measurement of the neutron magnetic form factor using quasielastic scattering from the mirror nuclei ^{3}H and ^{3}He, where the nuclear effects are larger than for deuterium but expected to largely cancel in the cross-section ratios. We extracted values of the neutron magnetic form factor for low-to-modest momentum transfer, 0.6 Collapse

Key Words Collapse

MESH Headings Collapse

Grants Collapse

Affiliation(s)

S N Santiesteban University of New Hampshire, Durham, New Hampshire 03824, USA
S Li University of New Hampshire, Durham, New Hampshire 03824, USA Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
D Abrams University of Virginia, Charlottesville, Virginia 22904, USA
S Alsalmi Kent State University, Kent, Ohio 44240, USA King Saud University, Riyadh 11451, Kingdom of Saudi Arabia
D Androic University of Zagreb, Zagreb, Croatia
K Aniol California State University, Los Angeles, California 90032, USA
J Arrington Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Argonne National Laboratory, Lemont, Illinois 60439, USA
T Averett William and Mary, Williamsburg, Virginia 23185, USA
C Ayerbe Gayoso William and Mary, Williamsburg, Virginia 23185, USA
J Bane University of Tennessee, Knoxville, Tennessee 37966, USA
S Barcus William and Mary, Williamsburg, Virginia 23185, USA
J Barrow University of Tennessee, Knoxville, Tennessee 37966, USA Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
A Beck Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
V Bellini INFN Sezione di Catania, Italy
H Bhatt Mississippi State University, Mississippi State, Mississippi 39762, USA
D Bhetuwal Mississippi State University, Mississippi State, Mississippi 39762, USA
D Biswas Hampton University, Hampton, Virginia 23669, USA
A Camsonne Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
J Castellanos Florida International University, Miami, Florida 33199, USA
J Chen William and Mary, Williamsburg, Virginia 23185, USA
J-P Chen Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
D Chrisman Michigan State University, East Lansing, Michigan 48824, USA
M E Christy Hampton University, Hampton, Virginia 23669, USA Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
C Clarke Stony Brook, State University of New York, New York 11794, USA
S Covrig Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
R Cruz-Torres Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
D Day University of Virginia, Charlottesville, Virginia 22904, USA
D Dutta Mississippi State University, Mississippi State, Mississippi 39762, USA
E Fuchey University of Connecticut, Storrs, Connecticut 06269, USA
C Gal University of Virginia, Charlottesville, Virginia 22904, USA
F Garibaldi INFN, Rome, Italy
T N Gautam Hampton University, Hampton, Virginia 23669, USA
T Gogami Tohoku University, Sendai, Japan
J Gomez Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
P Guèye Hampton University, Hampton, Virginia 23669, USA Michigan State University, East Lansing, Michigan 48824, USA
T J Hague Kent State University, Kent, Ohio 44240, USA
J O Hansen Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
F Hauenstein Old Dominion University, Norfolk, Virginia 23529, USA
W Henry Temple University, Philadelphia, Pennsylvania 19122, USA
D W Higinbotham Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
R J Holt Argonne National Laboratory, Lemont, Illinois 60439, USA
C Hyde Old Dominion University, Norfolk, Virginia 23529, USA
K Itabashi Tohoku University, Sendai, Japan
M Kaneta Tohoku University, Sendai, Japan
A Karki Mississippi State University, Mississippi State, Mississippi 39762, USA
A T Katramatou Kent State University, Kent, Ohio 44240, USA
C E Keppel Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
P M King Ohio University, Athens, Ohio 45701, USA
L Kurbany University of New Hampshire, Durham, New Hampshire 03824, USA
T Kutz Stony Brook, State University of New York, New York 11794, USA
N Lashley-Colthirst Hampton University, Hampton, Virginia 23669, USA
W B Li William and Mary, Williamsburg, Virginia 23185, USA
H Liu Columbia University, New York, New York 10027, USA
N Liyanage University of Virginia, Charlottesville, Virginia 22904, USA
E Long University of New Hampshire, Durham, New Hampshire 03824, USA
A Lovato Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA Computational Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA INFN-TIFPA Trento Institute for Fundamental Physics and Applications, 38123 Trento, Italy
J Mammei University of Manitoba, Winnipeg, MB R3T 2N2, Canada
P Markowitz Florida International University, Miami, Florida 33199, USA
R E McClellan Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
F Meddi INFN, Rome, Italy
D Meekins Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
R Michaels Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
M Mihovilovič Jožef Stefan Institute, 1000 Ljubljana, Slovenia Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, DE-55128 Mainz, Germany
A Moyer Christopher Newport University, Newport News, Virginia 23606, USA
S Nagao Tohoku University, Sendai, Japan
D Nguyen University of Virginia, Charlottesville, Virginia 22904, USA
M Nycz Kent State University, Kent, Ohio 44240, USA
M Olson Saint Norbert College, De Pere, Wisconsin 54115, USA
L Ou Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
V Owen William and Mary, Williamsburg, Virginia 23185, USA
C Palatchi University of Virginia, Charlottesville, Virginia 22904, USA
B Pandey Hampton University, Hampton, Virginia 23669, USA
A Papadopoulou Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
S Park Stony Brook, State University of New York, New York 11794, USA
T Petkovic University of Zagreb, Zagreb, Croatia
S Premathilake University of Virginia, Charlottesville, Virginia 22904, USA
V Punjabi Norfolk State University, Norfolk, Virginia 23529, USA
R D Ransome Rutgers University, New Brunswick, New Jersey 08854, USA
P E Reimer Argonne National Laboratory, Lemont, Illinois 60439, USA
J Reinhold Florida International University, Miami, Florida 33199, USA
S Riordan Argonne National Laboratory, Lemont, Illinois 60439, USA
N Rocco Theoretical Physics Department, Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
V M Rodriguez División de Ciencias y Tecnología, Universidad Ana G. Méndez, Recinto de Cupey, San Juan 00926, Puerto Rico
A Schmidt Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
B Schmookler Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
E P Segarra Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
A Shahinyan Yerevan Physics Institute, Yerevan, Armenia
S Širca Jožef Stefan Institute, 1000 Ljubljana, Slovenia Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia
K Slifer University of New Hampshire, Durham, New Hampshire 03824, USA
P Solvignon University of New Hampshire, Durham, New Hampshire 03824, USA
T Su Kent State University, Kent, Ohio 44240, USA
R Suleiman Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
L Tang Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
Y Tian Syracuse University, Syracuse, New York 13244, USA
W Tireman Northern Michigan University, Marquette, Michigan 49855, USA
F Tortorici INFN Sezione di Catania, Italy
Y Toyama Tohoku University, Sendai, Japan
K Uehara Tohoku University, Sendai, Japan
G M Urciuoli INFN, Rome, Italy
D Votaw Michigan State University, East Lansing, Michigan 48824, USA
J Williamson University of Glasgow, Glasgow, G12 8QQ Scotland, United Kingdom
B Wojtsekhowski Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
S Wood Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
Z H Ye Argonne National Laboratory, Lemont, Illinois 60439, USA Tsinghua University, Beijing, China
J Zhang University of Virginia, Charlottesville, Virginia 22904, USA
X Zheng University of Virginia, Charlottesville, Virginia 22904, USA

Collapse

The social and emotional wellbeing needs of Aboriginal staff in out of home care: Walking in two worlds

BACKGROUND

There is a disproportionate representation of Aboriginal children in the Australian Out of Home Care system. An important strategy to ensure Aboriginal children experience trauma informed care that is culturally situated is to have access to Aboriginal practitioners. The experiences of Aboriginal practitioners working in Aboriginal Out of Home Care have not been explored thoroughly.

PARTICIPANTS AND SETTING

This community led research was undertaken on Dharawal Country on the South Coast of the Illawarra region, Australia with an Out of Home Care program managed by an Aboriginal Community Controlled Organisation. The study included Aboriginal (n = 50) and non-Aboriginal (n = 3) participants connected through employment or community membership to the organisation.

OBJECTIVE

We aimed to explore the wellbeing needs of Aboriginal practitioners working with Aboriginal children in Aboriginal Out of Home Care.

METHODS

This co-designed qualitative research project used yarning sessions (individual and group), co-analysis with co-researchers, document analysis and reflexive writing.

FINDINGS

Aboriginal practitioners are required to bring their cultural expertise to their work and with this, there is an expectation of cultural leadership and the fulfilling of cultural responsibilities. These elements bring with them emotional labour that must be acknowledged and accounted for in working in the Out of Home Care sector.

CONCLUSION

The findings point to the importance of establishing an organisational social and emotional wellbeing framework in recognition of Aboriginal practitioner's specific needs, centring cultural participation as a key wellbeing and trauma informed strategy.

Measured proton electromagnetic structure deviates from theoretical predictions

The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton's bound state. A fundamental property of the proton involves the response of the system to an external electromagnetic field. It is characterized by the electromagnetic polarizabilities¹ that describe how easily the charge and magnetization distributions inside the system are distorted by the electromagnetic field. Moreover, the generalized polarizabilities² map out the resulting deformation of the densities in a proton subject to an electromagnetic field. They disclose essential information about the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents. Of particular interest is a puzzle in the electric generalized polarizability of the proton that remains unresolved for two decades². Here we report measurements of the proton's electromagnetic generalized polarizabilities at low four-momentum transfer squared. We show evidence of an anomaly to the behaviour of the proton's electric generalized polarizability that contradicts the predictions of nuclear theory and derive its signature in the spatial distribution of the induced polarization in the proton. The reported measurements suggest the presence of a new, not-yet-understood dynamical mechanism in the proton and present notable challenges to the nuclear theory.

Precision Determination of the Neutral Weak Form Factor of ^{48}Ca

We report a precise measurement of the parity-violating (PV) asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{48}Ca. We measure A_{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(q=0.8733  fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and the charge minus the weak form factor F_{ch}-F_{W}=0.0277±0.0055. The resulting neutron skin thickness R_{n}-R_{p}=0.121±0.026(exp)±0.024(model)  fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.

Deeply Virtual Compton Scattering Cross Section at High Bjorken x_{B}

We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable x_{B}. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of x_{B}, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

New Measurements of the Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering over a Range of Spin-0 Nuclei

We report precision determinations of the beam-normal single spin asymmetries (A_{n}) in the elastic scattering of 0.95 and 2.18 GeV electrons off ^{12}C, ^{40}Ca, ^{48}Ca, and ^{208}Pb at very forward angles where the most detailed theoretical calculations have been performed. The first measurements of A_{n} for ^{40}Ca and ^{48}Ca are found to be similar to that of ^{12}C, consistent with expectations and thus demonstrating the validity of theoretical calculations for nuclei with Z≤20. We also report A_{n} for ^{208}Pb at two new momentum transfers (Q^{2}) extending the previous measurement. Our new data confirm the surprising result previously reported, with all three data points showing significant disagreement with the results from the Z≤20 nuclei. These data confirm our basic understanding of the underlying dynamics that govern A_{n} for nuclei containing ≲50 nucleons, but point to the need for further investigation to understand the unusual A_{n} behavior discovered for scattering off ^{208}Pb.

Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering

We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q^{2}) up to 15.75  (GeV/c)^{2}. Combined with existing data, these provide an improved extraction of the proton magnetic form factor at high Q^{2} and double the range over which a longitudinal or transverse separation of the cross section can be performed. The difference between our results and polarization data agrees with that observed at lower Q^{2} and attributed to hard two-photon exchange (TPE) effects, extending to 8  (GeV/c)^{2} the range of Q^{2} for which a discrepancy is established at >95% confidence. We use the discrepancy to quantify the size of TPE contributions needed to explain the cross section at high Q^{2}.

Study of Λn FSI with Λ quasi-free productions on the 3H(e, e′K+)X reaction at JLab

Abstract. An nnΛ is a neutral baryon system with no charge. The study of the pure Λ-neutron system such as nnΛ gives us information on the Λn interaction. The nnΛ search experiment (E12-17-003) was performed at JLab Hall A in 2018. In this article, the Λn FSI was investigated by a shape analysis of the 3H(e, e′K+)X missing mass spectrum, and a preliminary result for the Λn FSI study is given.

Cross-section measurement of virtual photoproduction of iso-triplet three-body hypernucleus, Λnn

Missing-mass spectroscopy with the 3H(e, e′K+) reaction was carried out at Jefferson Lab’s (JLab) Hall A in Oct–Nov, 2018. The differential cross section for the 3H(γ∗, K+)Λnn was deduced at ω = Ee − Ee′ = 2.102 GeV and at the forward K+-scattering angle (0° ≤ θγ∗K ≤ 5°) in the laboratory frame. Given typical predicted energies and decay widths, which are (BΛ, Γ) = (−0.25, 0.8) and (−0.55, 4.7) MeV, the cross sections were found to be 11.2 ± 4.8(stat.)+4.1−2.1(sys.) and 18.1 ± 6.8(stat.)+4.2−2.9(sys.) nb/sr, respectively. The obtained result would impose a constraint for interaction models particularly between Λ and neutron by comparing to theoretical calculations.

Study of the Λ/Σ0 electroproduction in the low-Q2 region at JLab

We performed an experiment using tritium and hydrogen cryogenic gas targets at Thomas Jefferson National Accelerator Facility (JLab) in 2018 (E12-17-003)[1, 2]. In this article, we discuss the Λ/Σ0 hyperon electroproduction from hydrogen target. Elementary Λ/Σ0 hyperon production processes are important not only for an absolute mass scale calibration in our experiment, but also for the study of the electroproduction mechanisms themselves. In this article, we reported the results of the differential cross section for the p(e, e’K+)Λ/Σ0 reaction at Q2 ∼ 0.5 (GeV/c)2.

Deep Exclusive Electroproduction of π^{0} at High Q^{2} in the Quark Valence Regime

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of x_{B} (0.36, 0.48, and 0.60) and Q^{2} (3.1 to 8.4  GeV^{2}) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσ_{T}/dt+εdσ_{L}/dt, dσ_{TT}/dt, dσ_{LT}/dt, and dσ_{LT^{'}}/dt are extracted as a function of the proton momentum transfer t-t_{min}. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

Accurate Determination of the Neutron Skin Thickness of ^{208}Pb through Parity-Violation in Electron Scattering

We report a precision measurement of the parity-violating asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{208}Pb. We measure A_{PV}=550±16(stat)±8(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(Q^{2}=0.00616  GeV^{2})=0.368±0.013. Combined with our previous measurement, the extracted neutron skin thickness is R_{n}-R_{p}=0.283±0.071  fm. The result also yields the first significant direct measurement of the interior weak density of ^{208}Pb: ρ_{W}^{0}=-0.0796±0.0036(exp)±0.0013(theo)  fm^{-3} leading to the interior baryon density ρ_{b}^{0}=0.1480±0.0036(exp)±0.0013(theo)  fm^{-3}. The measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and composition of neutron stars.

Pentraxin-3 is a PI3K signaling target that promotes stem cell-like traits in basal-like breast cancers

Basal-like breast cancers (BLBCs) exhibit hyperactivation of the phosphoinositide 3-kinase (PI3K) signaling pathway because of the frequent mutational activation of the PIK3CA catalytic subunit and the genetic loss of its negative regulators PTEN (phosphatase and tensin homolog) and INPP4B (inositol polyphosphate-4-phosphatase type II). However, PI3K inhibitors have had limited clinical efficacy in BLBC management because of compensatory amplification of PI3K downstream signaling loops. Therefore, identification of critical PI3K mediators is paramount to the development of effective BLBC therapeutics. Using transcriptomic analysis of activated PIK3CA-expressing BLBC cells, we identified the gene encoding the humoral pattern recognition molecule pentraxin-3 (PTX3) as a critical target of oncogenic PI3K signaling. We found that PTX3 abundance is stimulated, in part, through AKT- and nuclear factor κB (NF-κB)-dependent pathways and that presence of PTX3 is necessary for PI3K-induced stem cell-like traits. We further showed that PTX3 expression is greater in tumor samples from patients with BLBC and that it is prognostic of poor patient survival. Our results thus reveal PTX3 as a newly identified PI3K-regulated biomarker and a potential therapeutic target in BLBC.

Abstract 2634: Investigating the chemotherapeutic effects of aspirin in mutant PIK3CA breast cancer

Although aspirin is primarily administered as an antipyretic and analgesic, numerous observational and randomized clinical trials have suggested a potential chemotherapeutic use. Recently, two independent studies demonstrated that aspirin use is associated with superior survival in colorectal cancer patients with mutant-PIK3CA but not among those with the wild-type gene. Despite these seminal observations, the molecular basis for this phenomenon remains poorly understood. Furthermore, whether this observation occurs in breast cancer is unknown. Given that (1) mutation of PIK3CA, the gene encoding the catalytic subunit of the phosphoinositide 3-kinase (PI 3-K) is highly prevalent in breast cancer and that (2) aspirin use is associated with a decrease in breast cancer mortality and distant recurrence, the relationship between PI 3-K pathway activation and the protective benefit of aspirin in breast cancer was investigated. Here, we utilize both PIK3CA mutant breast cancer cell lines and a well-characterized system of immortalized mammary epithelial cells stably expressing either wild-type and mutant PIK3CA E545K and H1047R respectively. Mutant PIK3CA breast cancer cells show a dose-dependent decrease in cell viability with increasing concentration of aspirin/salicylate. In these cells, co-treatment of aspirin with PI 3-K pathway inhibitors BYL719 or BKM120 caused a more significant decrease on cell growth compared to each single agent alone. In 3D culture, MCF10A cells expressing mutant PIK3CA-H1047R showed greater sensitivity to aspirin compared to cells expressing wild-type PIK3CA. Gene expression profiling and quantitative qRT-PCR was employed to identify and validate mutant PIK3CA-regulated genes respectively. Many of these genes were associated with inflammation; among them was the PTGS2 gene which encodes for cyclooxygenase-2 (COX-2). We observed that mutant PIK3CA regulates cyclooxygenase-2 (COX-2) mRNA and protein expression as well as production of prostaglandin E2α (PGE2α). Expression of mutant PIK3CA also increases phosphorylation of IKKβ and IκB; increases mTORC1 signaling and reduces AMPK activity. This is abrogated upon pharmacologic inhibition of mutant PIK3CA with BYL719 and BKM120. Notably, both aspirin and its metabolite salicylate can inhibit these PIK3CA-induced pathways and activate AMPK signaling. An understanding of these key survival and metabolic signaling pathways, which are modulated by aspirin, may help to explain aspirin's beneficial effect in PIK3CA-mutant breast cancers. Given the growing interest in personalized medicine, this pre-clinical study may provide insight for the stratification of patients who are most likely to benefit from adjuvant aspirin therapy.

Citation Format: Whitney Henry, Alex Toker. Investigating the chemotherapeutic effects of aspirin in mutant PIK3CA breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2634. doi:10.1158/1538-7445.AM2015-2634

The effect of level of crude protein and available lysine on finishing pig performance, nitrogen balance and nutrient digestibility

Two trials were conducted to investigate the effect of decreasing the crude protein (CP) content of diets for finishing pigs containing two levels of available lysine on nutrient digestibility, nitrogen (N) balance and production performance. Ten finishing diets containing five levels of CP (on average 144, 155, 168, 182 and 193 g/kg fresh basis) and two levels of available lysine (6.9 and 8.2 g/kg fresh basis) were formulated. The diets were offered to pigs on a performance trial (n = 800 Large White (LW)×Landrace (LR) pigs) from 10 wk of age until finish at 21 wks+5 d of age. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated. In addition, a digestibility/N balance trial was conducted using pigs (n = 80 LW×LR) housed in metabolism crates. Digestibility of dry matter (DM), CP, oil, fibre and energy was determined. N balance values were determined through analysis of N content of urine and faeces (‘as determined’). N balance values were also calculated using ADG values and assuming that 16% of growth is protein deposition (“as calculated”). Pig performance was poor between 10 and 13 wk of age which indicated that the dietary treatments were nutritionally inadequate for pigs less than 40 kg. There was a significant (p<0.01) quadratic effect of increasing CP level on feed intake, ADG and FCR from 10 to 13 wk which indicated that the lower CP levels did not supply adequate levels of essential or non-essential amino acids. There was no effect of increasing available lysine level throughout the early period, which in conjunction with the response in older pigs, suggested that both 8.2 and 6.9 g/kg available lysine were insufficient to drive optimum growth. There was a positive response (p<0.05) to increasing available lysine level from 13 wk to finish which indicated that 6.9 g/kg available lysine was not adequate for finishing pigs. Energy digestibility decreased with decreasing CP level of diets containing 6.9 g/kg available lysine which may be attributed to the higher fibre content of the lower CP diets. Nitrogen excretion (g/d) was lowered when dietary CP was reduced regardless of whether the values were determined through balance or calculated using ADG. Calculated N excretion decreased linearly (p<0.001) and quadratically (p<0.001) with decreasing dietary CP content. When the N balance figures calculated in this study were compared with those quoted in the Northern Ireland and English Nitrates Directive Action Programmes, N excretion was less per pig (wean to finish) offered a 169 g/kg CP, 8.2 g/kg available lysine diet (2.39 kg vs 3.41 kg (Northern Ireland) and 2.93 kg (England)).

African dust clouds are associated with increased paediatric asthma accident and emergency admissions on the Caribbean island of Trinidad

A retrospective ecological study of paediatric asthma patients who attended the Accident and Emergency (A and E) department of the Paediatric Priority Care Facility at the Eric Williams Medical Sciences Complex in relation to Saharan dust visibility and other climatic variables for the period 23 May 2001 to 13 May 2002 was undertaken to determine if there is an association between paediatric A and E asthma visits and Saharan dust cloud cover. A Poisson regression model was used to determine the statistical relationship between acute paediatric asthma A and E visits and Saharan dust cover with and without other variables such as climatic parameters and month. During the study period, there were 2,655 A and E visits for acute asthma. There was an association between increased paediatric asthma admissions and increased Saharan dust cover. The best fitting model estimated that in one month, such as June, a deterioration of visibility due to increased Saharan dust cover from no dust (visibility =16 km) to very dusty (visibility =7 km) would increase a daily admission rate of 7.8 patients to 9.25 when climate variables such as barometric pressure and humidity were kept constant.

Environmental influences on the failure to drink in inbred rats with an ethanol preference

To investigate the environmental influences on the initiation of voluntary consumption of 10% ethanol (EtOH) in rats with differing genetic susceptibility to excessive EtOH consumption, Maudsley reactive (MR/Har) and nonreactive (MNRA/Har) inbred rats were observed in different types of caging environments. Singly housed male and female rats of both strains living in Observational (O) cages drank markedly less EtOH during 3 weeks of two-bottle choice than did rats living in standard-control (C) individual cages. When male rats had a preexisting moderate or heavy pattern of EtOH intake (manipulated through prior EtOH experience), moving to the O cage did not reduce EtOH intake. To investigate the nature of the above cage effect (the reduced initiation of EtOH consumption), we compared the manner in which food had been distributed (traditional food hopper in C cages versus loose distribution in O cages) independently of cage type. The results showed that MR/Har male rats that obtained food through a hopper in both O or C cages drank significantly more EtOH than rats that had food loosely distributed in the O or C cages. The results suggest that differences in the mode of food procurement and caging can play a large role in whether the phenotype for excessive EtOH intake is expressed in the acquisition of an EtOH preference in genetically vulnerable rats.

Vasoreactivity and structure of human coronary arteries irradiated by excimer laser

In this study the effects of excimer laser (308 nm) angioplasty on arteries have been studied. We report histology and vasoreactivity properties of human atherosclerotic and normal coronary arteries and bovine coronary arteries after exposure to pulsed excimer laser irradiation. Segments of isolated and pharmacologically active human coronary arteries were obtained within 5-8 hr postmortem. Segments of bovine arteries were obtained from fresh hearts. Side branches were ligated and vessels perfused with Krebs-Ringer's-bicarbonate solution in a perfusion apparatus to maintain their viability. Excimer laser irradiation was performed using a fused silica fiber advanced through the artery within a polyethylene cannula to assist with steerability and to protect against perforation. The fiber delivered a total of 40-60 J at its tip at 100 mJ/pulse at 15 pulses/sec. A total of 5 human atherosclerotic, 2 human normal, and 8 bovine arteries were used. Ablation of plaque was accomplished with remarkable ease and little resistance. Histologic studies showed clear-cut wedges inscribed by the catheter along the arterial wall without charring or thermal effects of coagulation necrosis. Vasoreactivity was assessed by measuring flow changes during perfusion before and after excimer angioplasty using a transient challenge with the vasoconstrictor serotonin. All excimer-irradiated arteries showed no increase in vasoreactivity during the challenge and showed preservation of relaxation properties following the challenge. In conclusion, coronary artery angioplasty by excimer laser appears to allow for effective plaque ablation with simultaneous preservation of structure and pharmacological properties of arteries.

A joint venture with the commonwealth of independent states

One hesitates to comment on the frequent alterations occurring in the former Soviet Union (or disunion, as one Russian recently commented). Since Mr. Gorbachev first wrote of perestroika in 1987, the changes have been beyond imagination, and the future remains totally unpredictable.

Increased serum apolipoprotein(a) in patients with chronic renal failure treated with continuous ambulatory peritoneal dialysis

Patients with end-stage renal failure (ESRF) on renal replacement therapy are at significantly increased risk of cardiovascular disease. To determine whether altered concentrations of apolipoprotein(a) (apo(a)), the plasminogen-like protein moiety of the atherogenic particle lipoprotein(a), contributed to this increased risk, apo(a) concentrations were measured in 48 non-diabetic patients with ESRF treated by continuous ambulatory peritoneal dialysis (CAPD) therapy and compared with 65 controls. Apo(a) concentration was increased in CAPD patients compared to controls (geometric mean 419 units/l versus 137 units/l; ratio of means 3.06 (95% CI 1.95-4.80). We conclude that CAPD patients have increased apo(a) concentrations which may contribute to their increased risk of cardiovascular disease.

Hemodynamic effects of endothelin-1 in the newborn piglet: influence on pulmonary and systemic vascular resistance

The aim of this study was to investigate the influence of endothelin-1 (ET-1) on the pulmonary and systemic circulations in newborn piglets. Twelve piglets (mean age of 6.8 days, range of 1-12 days) were anesthetized with chloralose-urethane and ventilated at FiO2 = 1.0. Animals were instrumented to measure cardiac output (CO), pulmonary artery pressure (PAP), aortic pressure (AoP), left atrial pressure (LAP), and right atrial pressure (RAP). Six piglets received a control saline injection into the pulmonary artery (PA), and six piglets received one injection of ET-1 (500 ng/kg) into the PA while PAP, AoP, LAP, RAP, CO, and heart rate (HR) were measured simultaneously at 20-s intervals with pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR) calculated by computer. Administration of ET-1 into the PA led to (a) a transient decrease in mean PAP (delta max of -4 +/- 2 mm Hg, p less than 0.001); (b) a biphasic response (an initial decline followed by a substantial increase) in PVR (delta max of -760 +/- 460 dyn cm/s5, p less than 0.01, and delta max of +1,490 +/- 1,360 dyn cm/s5, p less than 0.05) and in AoP (delta max of -12 +/- 7 mm Hg, p less than 0.005, and delta max of +11 +/- 6 mm Hg, p less than 0.005); (c) an increase in SVR (delta max of +5,930 +/- 2,330 dyn cm/s5, p less than 0.05); and (d) an initial increase in CO (delta max of +0.06 +/- 0.03 L/min, p less than 0.05) followed by a decrease (delta max of -0.09 +/- 0.05 L/min, p less than 0.05). These responses have not been observed in adult species and may indicate a developmental difference in the response of the pulmonary circulation to ET-1 administration.

Tax-exempt challenges warrant hospitals' attention

The tax-exempt status of not-for-profit healthcare organizations is being questioned and sometimes challenged on Federal, state, and local fronts. While the Internal Revenue Service (IRS) has created a special program for randomly auditing not-for-profit organizations, Congress is expected to consider legislation that would mandate the amount of charity care and community benefits a tax-exempt hospital must provide in relation to its tax-exemption value. Familiarity with IRS and Congressional activity, as well as with cases in which a hospital's tax-exempt status has been challenged in court, may provide guidelines for hospitals to assess their vulnerability.

Laser-assisted thermal angioplasty in human peripheral artery occlusions: mechanism of recanalization

Recanalization of completely occluded superficial femoral or popliteal arteries was attempted in 18 patients with use of an Argon laser-mediated thermal probe. The length of the occluded segments varied between 0.5 and 26.0 cm, but 67% of the occlusions were greater than 9 cm long. The initial success rate was 67%. Arterial perforation occurred in six patients but was not associated with major complications. To study the mechanism of the laser-mediated thermal probe, thermal recanalization was performed on 11 human arterial segments in vitro obtained after amputation, and mechanical recanalization was performed in vitro in 10 human peripheral arteries with use of a guide wire and catheter technique. An additional four arteries were studied with the laser probe as a non-heated mechanical device. Both the mechanical and thermal devices appear to follow a similar pathway through a complete obstruction. These studies suggest that the thermal probe burns through soft fibrous tissue but is mechanically deflected away from hard fibrocalcific plaque. The probe then advances along the plane between the intimal plaque and the media for a variable length before perforating through the adventitia. These observations suggest that the major mechanism of thermal probe recanalization may be a mechanical process. It appears that thermal probe devices do not inherently seek the true lumen of an occluded artery and that better guidance systems need to be developed.

Isoniazid preventive therapy for tuberculosis. Are we losing our enthusiasm?

Contact investigation activities of the Tennessee Department of Health and Environment (TDHE) Tuberculosis (TB) Control Program from 1979 to 1985 were reviewed. Out of 32,722 identified contacts, 6,030 (20.1 percent) were infected (positive purified protein derivative [PPD]). Only 2,731 (45 percent) of the infected contacts were started on preventive therapy. Both the absolute number and the relative percentage of infected contacts starting on INH prevention therapy have gradually declined over the years. While 569 (67 percent) of the infected contacts were started on preventive treatment in 1979, only 296 (37.5 percent) received isoniazid (INH) preventive therapy in 1985. Although an increasing percentage of those starting preventive therapy completed the prescribed course, the enthusiasm for recommending preventive therapy has declined for the infected individuals above the age of 15. More enthusiasm and efforts are needed from physicians in initiating and maintaining INH preventive therapy to accomplish tuberculosis eradication.

Glutamine metabolism in rat skeletal muscle wounded with lambda-carrageenan

Wounding with lambda-carrageenan results in a marked decrease in the intracellular-free glutamine content of rat skeletal muscle. The potential mechanisms for this finding, including alterations in glutamine release, glutamine utilization, and glutamine synthesis, were investigated in rats under pentobarbital anesthesia. Wounding did not increase glutamine release from muscle during incubation or isolated hindlimb perfusion. Wounded muscle utilized more glutamine than nonwounded muscle, as measured both by the production of [14C]O2 and of -glutamate from labeled glutamine. Maximal glutamine synthetase activity was increased by wounding. The increase in glutamine synthetase activity in wounded muscle was prevented by adrenalectomy and restored by replacement doses of corticosterone in wounded adrenalectomized animals. The decrease in muscle free glutamine induced by wounding is therefore not mediated by an increase in the release of this amino acid, nor by a reduction in the tissue capacity for glutamine synthesis, but by an increase in glutamine utilization at the site of injury. This difference is apparently determined by the utilization of glutamine by the cellular components of the inflammatory infiltrate, which were shown to be capable of active glutaminolysis.

The relationship of purine metabolism to the macrophage-mediated increase of high energy phosphates in skeletal muscle

Previous investigations have demonstrated that the high energy phosphate and adenine nucleotide content of wounded tissue are decreased. Purine metabolism was investigated in incubated lambda-carrageenan wounded skeletal muscle and in muscle exposed to peritoneal macrophages or macrophage-conditioned media. Wounded muscle released predominately uric acid into the incubation medium; whereas, nonwounded muscle released inosine, hypoxanthine, and xanthine as well as uric acid. Macrophages incubated with nonwounded muscle changed the purine release pattern toward one of wounded muscle. The conversion of inosine to allantoin and uric acid by macrophages increased linearly with the addition of up to 1 X 10(7) macrophages per incubation. Muscles incubated in macrophage-conditioned media had a decreased release of inosine and hypoxanthine and higher tissue levels of creatine phosphate, ATP, ADP, AMP, and adenosine compared to muscles incubated in standard media. These data suggest that the macrophage determines the pattern of purine release from wounded skeletal muscle in the incubated system and that in conditioned media a high energy phosphate promoting factor may exert its effect by mechanisms that augment the adenine purine pool.

Macrophage interaction with skeletal muscle: a potential role of macrophages in determining the energy state of healing wounds

A decrease in ATP and creatine phosphate (CP) is characteristic of local injury to skeletal muscle. Recent data have suggested adequate potential for high-energy phosphate production in the wounded tissue. Thus, an adequate explanation for the deficit in the high-energy tissue content in wounds was lacking. Since the wound has multiple components (muscle + cellular infiltrate), the tissue content represents the summation of these components. Therefore, a technique to separate these components was designed. Using a 0.5% solution of lambda-carrageenan as the wounding agent, the extensor digitorum longus muscles (EDL) of male Fisher rats were unilaterally wounded with intramuscular injections. Five days later, both wounded and contralateral nonwounded muscles were incubated in a standardized fashion. The groups of EDL were: wounded as described, contralateral nonwounded, or contralateral nonwounded with the addition to the incubate of 6 X 10(6)/ml lambda-carrageenan elicited peritoneal macrophages. Following incubation, the individual component parts of the system (muscle and macrophage) were rapidly frozen and assayed for high-energy phosphate and DNA content. Examination of the high-energy phosphate content of the separate components of a wound demonstrated that macrophages increased the ATP and CP content of normal skeletal muscle. Yet when total high-energy phosphate content was normalized for total DNA (muscle + macrophages) in the reconstituted system, the values approximated those of wounded muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Digital coronary roadmapping as an aid for performing coronary angioplasty

In an attempt to improve visualization of the position of the guidewire and dilatation balloon during coronary angioplasty, a method was developed called digital coronary roadmapping. With this method a digitally acquired coronary angiogram is interlaced with the live fluoroscopic image of the guidewire and balloon catheter. The digital coronary angiogram is superimposed at the same magnification and radiologic projection as the live fluoroscopic image onto the video monitor above the catheterization table. The digital roadmap image thus provides immediate feedback to the angiographer to assist in directing the guidewire into the appropriate coronary artery branch and to help in placement of the balloon so that it straddles the site of stenosis.

A macrophage-mediated factor that increases the high energy phosphate content of skeletal muscle

A marked cellular infiltrate accompanies wounding. The phagocytic and bacteriocidal activities of this infiltrate require increased substrate and O2 consumption. This rapid utilization of available oxygen and substrates could jeopardize an already compromised resident cellular component of a wound. Recent studies have demonstrated macrophage-mediated cell stimulatory agents which induce proliferation of nonlymphoid mesenchymal cells. This study was designed to examine macrophage-resident tissue interactions and their possible significance in wounded tissue. A reconstituted wound system was designed which combines the major components of a lambda-carrageenan skeletal muscle wound (muscle + macrophages). The extensor digitorum longi (EDL) of male Fisher rats were incubated in a standardized fashion. The groups of EDL were muscle incubated alone, muscle with the addition to the incubate of activated peritoneal macrophages or muscle with the addition of a conditioned supernatant from the incubation of activated or nonactivated peritoneal macrophages. Muscle ATP and CP content were noted to be increased 46 and 22%, respectively, when macrophages and skeletal muscle were coincubated. Macrophage-conditioned media from activated or nonactivated macrophages increased the ATP and CP muscle content 44 and 37%, respectively. Preliminary characterization of this high energy phosphate (HEP) promoting factor demonstrates it to be heat and cold stable and less than 10,000 Da. Therefore, a macrophage-mediated transferable factor is capable of increasing the HEP content of skeletal muscle in an in vitro system. This may have important consequences in maintaining host cell integrity following injury.

Evidence for aerobic glycolysis in lambda-carrageenan-wounded skeletal muscle

Classically, increased lactate production in wounded tissue is ascribed to anaerobic glycolysis although its oxygen consumption has been found to be similar to normal tissue. This apparent inconsistency was studied in a standardized isolated perfused wound model. Male Sprague-Dawley rats were wounded (group W) with intramuscular injections of lambda-carrageenan and fed ad lib.; not wounded and pair fed to the decreased food intake of the wounded animals (group PFC); or not wounded and fed ad lib. (group ALC). After 5 days, the hindlimbs of animals from each group were either perfused using a standard perfusate with added [U-14C]glucose or [1-14C]pyruvate or assayed for the tissue content of lactate and pyruvate. In addition, the effect of a 30% hemorrhage on the tissue lactate and pyruvate concentration was examined. Wounding increased glucose uptake and lactate production by 100 and 96%, respectively, above that seen in ALC animals. Oxygen consumption was unchanged by wounding (5.74, 5.14, and 5.83 mumole/min/100 g in W, PFC, and ALC, respectively). Glucose and pyruvate oxidation were also unaltered among the groups. Hemorrhage resulted in a comparable increase in lactate and pyruvate in tissue from wounded and pair-fed control animals (above those concentrations found in tissue harvested without preexisting hemorrhage). As a consequence, the same relationship in L/P ratio was maintained after hemorrhage. Taken together, these results confirm the presence of aerobic glycolysis in wounded tissue (unchanged oxygen consumption, glucose, and pyruvate oxidation). In addition, pyruvate dehydrogenase activity in the wound was apparently the same as that found in muscle from pair-fed control animals.

Life-threatening complications of varicella

We reviewed the records of 96 children hospitalized with varicella from July 1, 1975 to June 30, 1980. Eighty-one were immunologically normal and 15 were immunocompromised on the basis of neoplasia, immunosuppressive therapy, or genetic disease. These children experienced 106 complications including viral dissemination-encephalitis (44), bacterial infection (25), Reye's syndrome (17), unusual cutaneous lesions (eight), drug overdose (five), diabetic ketoacidosis (two), neonatal infection (two), dehydration (two), and exacerbation of preexisting nephrosis (one). The length of hospitalization varied from one to 38 days with a median of five days. There were ten varicella pneumonia (one), of neonatal varicella (one), and of a ruptured mycotic aneurysm secondary to septicemia (one). This review demonstrates (1) a substantial occurrence of life-threatening complications of varicella in childhood, and (2) a need for prospective epidemiologic data on the incidence of complications to determine the scope and extent of varicella vaccination.

Cellulitis: initial management

Although Staphylococcus aureus and Streptococcus pyogenes cause the majority of cellulitis, recent studies have shown a significant role for Hemophilus influenzae in facial, and less frequently, nonfacial infections. We devised an algorithm for the initial management of cellulitis based on our previous investigations showing a correlation of this organism with fever, leukocytosis, and facial involvement. Children were divided into four groups characterized as follows: Group I - extremity, temperature less than 38.5 C; Group II - extremity, temperature greater than 38.5 C, WBC less than 15,000/cu mm; Group III - extremity, temperature greater than 38.5 C, WBC greater than 15,000/cu mm; and Group IV - facial. Forty-five children were successfully followed. There were 34 in Group I, five in Group II, one in Group III, and five in Group IV. Two children in Group IV and the only child in Group III had H influenzae, recovered form the blood (3) or a direct aspirate (1). All three were febrile, with a range of 39.5 C to 40.1 C and has an elevated white blood cell count with a range of 19,200/cu mm to 26,000/cu mm. With one exception, children with cellulitis not due to H influenzae did not have both fever and leukocytosis. This algorithm allows the clinician to identify children with H influenzae cellulitis who are at risk for septic complications while minimizing unnecessary diagnostic or therapeutic interventions.

Hepatoma visualization with Tc-99m pyridoxylidene glutamate

Tc-99m sulfur colloid is concentrated in Kupffer cells of the liver, whereas the new biliary agents are processed by hepatic parenchymal cells. A case of primary hepatocellular carcinoma, appearing as a defect on sulfur-colloid liver scan and visualized on a biliary scan, is presented. The possible role of biliary scanning in the evaluation of a defect on sulfur-colloid liver scan is discussed.

Evaluation of cardiac function in patients with thalassemia major

The application of noninvasive techniques to the evaluation of cardiac function in iron overload has identified a high incidence of abnormalities in asymptomatic patients prior to the onset of overt cardiac deterioration. Of the tests we have used, radionuclide cineangiography appears to be the most sensitive because it can be conveniently applied during the physiological stress of exercise. Other tests of cardiac function that include stress are also likely to be more sensitive than resting measurements of cardiac function. Systematic application of these techniques to the study of patients on iron chelation therapy should results in an early determination of the efficacy of such treatment.