Lactate concentration gradient from right atrium to pulmonary artery

INTRODUCTION: We compared simultaneous measurements of blood lactate concentration ([Lac]) in the right atrium (RA) and in the pulmonary artery (PA). Our aim was to determine if the mixing of right atrial with coronary venous blood, having substantially lower [Lac], results in detectable decreases in [Lac] from the RA to the PA. METHODS: A prospective, sequential, observational study was conducted in a medical-surgical intensive care unit. We enrolled 45 critically ill adult individuals of either sex requiring pulmonary artery catheters (PACs) to guide fluid therapy. Immediately following the insertion of the PAC, one paired set of blood samples per patient was drawn in random order from the PAC's proximal and distal ports for measurement of hemoglobin concentration, O(2 )saturation (SO(2)) and [Lac]. We defined Δ[Lac] as ([Lac](ra )- [Lac](pa)), ΔSO(2 )as (S(ra)O(2 )- S(pa)O(2)) and the change in O(2 )consumption (ΔVO(2)) as the difference in systemic VO(2 )calculated using Fick's equation with either S(ra)O(2 )or S(pa)O(2 )in place of mixed venous SO(2). Data were compared by paired Student's t-test, Spearman's correlation analysis and by the method of Bland and Altman. RESULTS: We found S(ra)O(2 )> S(pa)O(2 )(74.2 ± 9.1 versus 69.0 ± 10.4%; p < 0.001) and [Lac](ra )> [Lac](pa )(3.9 ± 3.0 versus 3.7 ± 3.0 mmol.l(-1); p < 0.001). Δ[Lac] correlated with ΔVO(2 )(r(2 )= 0.34; p < 0.001). CONCLUSION: We found decreases in [Lac] from the RA to PA in this sample of critically ill individuals. We conclude that parallel decreases in SO(2 )and [Lac] from the RA to PA support the hypothesis that these gradients are produced by mixing RA with coronary venous blood of lower SO(2 )and [Lac]. The present study is a preliminary observation of this phenomenon and further work is needed to define the physiological and clinical significance of Δ[Lac]

Shock Breakout from Type Ia Supernova

The mode of explosive burning in Type Ia SNe remains an outstanding problem. It is generally thought to begin as a subsonic deflagration, but this may transition into a supersonic detonation (the DDT). We argue that this transition leads to a breakout shock, which would provide the first unambiguous evidence that DDTs occur. Its main features are a hard X-ray flash (~20 keV) lasting ~0.01 s with a total radiated energy of ~10^{40} ergs, followed by a cooling tail. This creates a distinct feature in the visual light curve, which is separate from the nickel decay. This cooling tail has a maximum absolute visual magnitude of M_V = -9 to -10 at approximately 1 day, which depends most sensitively on the white dwarf radius at the time of the DDT. As the thermal diffusion wave moves in, the composition of these surface layers may be imprinted as spectral features, which would help to discern between SN Ia progenitor models. Since this feature should accompany every SNe Ia, future deep surveys (e.g., m=24) will see it out to a distance of approximately 80 Mpc, giving a maximum rate of ~60/yr. Archival data sets can also be used to study the early rise dictated by the shock heating (at about 20 days before maximum B-band light). A similar and slightly brighter event may also accompany core bounce during the accretion induced collapse to a neutron star, but with a lower occurrence rate.Comment: Submitted for publication in The Astrophysical Journal on June 12, 2009; 7 pages, 5 figure

Solo versus collaborative writing: Discrepancies in the use of tables and graphs in academic articles

International audienceThe number of authors collaborating to write scientific articles has been increasing steadily. And, with this collaboration, other factors have also changed, such as the length of the articles and the number of citations. However, little is known about potential discrepancies in the use of tables and graphs between single and collaborating authors. In this paper we ask whether multi-author articles contain more tables and graphs than single-author articles and we studied 5,180 recent articles published in six science and social sciences journals. We found both that pairs and multiple-authors used significantly more tables and graphs than single authors. Such findings indicate that there is a greater emphasis on the role of tables and graphs in collaborative writing, and we discuss some of the possible causes and implications of these findings

Nucleotide sequence encoding the carboxyl-terminal half of apolipoprotein B from spontaneously hypercholesterolemic pigs.

Previous studies from this laboratory characterized the hypercholesterolemia of pigs with a mutant allele of apolipoprotein B (apoB), designated Lpb5. This apoB allele is associated with low density lipoprotein (LDL) particles deficient in binding to the LDL receptor. To identify potential causative mutations in Lpb5 DNA, 10.6 kb of genomic DNA, encoding the carboxyl-terminal 58% of apoB were sequenced from the Lpb5 allele and from an allele encoding phenotypically normal apoB. Comparison of the two DNA sequences revealed 33 polymorphisms, 13 of which resulted in amino acid polymorphisms. To determine whether any of the amino acids at the polymorphic positions in Lpb5-encoded apoB were unique to that isoform, those positions were sequenced in four other pig apoB alleles encoding phenotypically normal apoB. None of the amino acids were by themselves uniquely encoded by the Lpb5 allele. However, a unique haplotype consisting of Asp3164 in conjunction with Ala3447 distinguished the Lpb5-encoded apoB from all other allelic isoforms sequenced in this region. To gain insight into changes in the tertiary structure of the mutant apoB, 13C-NMR analysis of LDL reductively methylated with [13C]-formaldehyde was performed. LDL has lysine residues that titrate at pH 10.5 and others that titrate at pH 8.9. The latter residues are thought to include those involved in the interaction of LDL with the LDL receptor. LDL from Lpb5 pigs possessed a smaller proportion of lysine residues titrating at pH 8.9 than did LDL from non-Lpb5 pigs, suggesting that the Lpb5-encoded apoB is altered in a manner affecting the microenvironment of particular lysine residues

Evaluation of dietary quality of adolescents using Healthy Eating Index

The aim of this study was to use the Healthy Eating Index-2005 (HEI-2005) to assess diet quality and determine the relationship between the HEI-2005 and the energy and nutrient intakes of adolescents. A cross-sectional study was conducted on 1,104 healthy adolescents, mean age of 15.8 ± 1.24 years. Dietary intake was measured with the 24-hour dietary recall method, and dietary quality was assessed by means of the HEI-2005. Diet quality scores ranged from 23.7 to 77.5. The mean score was found to be 51.5 ± 9.07 according to the HEI-2005. There were no differences according to gender; 42.8% had a poor diet and 57.2% had a diet that needs improvement. No subjects had a "good diet". Lower mean subgroup scores were found for whole grains, total vegetables, total fruits, dairy products, and meat and beans. Fruits and vegetables scores were significantly high in girls, whereas sodium, oil, and meat and beans scores were significantly high in boys. Total HEI-2005 scores were increasingly associated with parental education level when age and gender were adjusted. There was a negative correlation between HEI-2005 scores and age, total energy intake, and fat intake. Positive correlation was only observed in the HEI-2005 scores for protein and dietary fibre intakes. Consequently, the overall diet quality and nutritional habits of Turkish adolescents need modification and improvement. In the family, measures should be initiated by the government, including advertisements and campaigns

Cardio-renal syndromes: report from the consensus conference of the Acute Dialysis Quality Initiative

A consensus conference on cardio-renal syndromes (CRS) was held in Venice Italy, in September 2008 under the auspices of the Acute Dialysis Quality Initiative (ADQI). The following topics were matter of discussion after a systematic literature review and the appraisal of the best available evidence: definition/classification system; epidemiology; diagnostic criteria and biomarkers; prevention/protection strategies; management and therapy. The umbrella term CRS was used to identify a disorder of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other organ. Different syndromes were identified and classified into five subtypes. Acute CRS (type 1): acute worsening of heart function (AHF–ACS) leading to kidney injury and/or dysfunction. Chronic cardio-renal syndrome (type 2): chronic abnormalities in heart function (CHF-CHD) leading to kidney injury and/or dysfunction. Acute reno-cardiac syndrome (type 3): acute worsening of kidney function (AKI) leading to heart injury and/or dysfunction. Chronic reno-cardiac syndrome (type 4): chronic kidney disease leading to heart injury, disease, and/or dysfunction. Secondary CRS (type 5): systemic conditions leading to simultaneous injury and/or dysfunction of heart and kidney. Consensus statements concerning epidemiology, diagnosis, prevention, and management strategies are discussed in the paper for each of the syndromes

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p