296 research outputs found
Strength tests on asphalt mixes attacked by motor fuels. Recommendations on bath immersion times
[Abstract:] One of the limitations of asphalt mixes as pavement materials is their poor resistance to attack from crude oil-based motor fuels. Several procedures exist for determining the resistance of asphalt materials to motor fuel action. Different test standards can be found for fillers and surface dressings in both the US and European series. However, where the assessment of asphalt mixes themselves are concerned, there is a considerable lack of standardisation. This paper reports on laboratory studies on certain essential aspects of the procedures for assessing the strength of asphalt mixes in respect of motor fuel attack, chiefly the time the mix is exposed to the fuel. Based on the research results, the paper makes some good-practice recommendations for weight-loss procedures after immersion in motor fuel, with or without subsequent brushing, and in respect of the Marshall stability preserved after immersion. In relation to the immersion period and in view of the laboratory findings and their subsequent statistical processing, one of the factors with the greatest influence is the recommendation that the immersion period should be 24 hours, except in the weight-loss test subseuent to immersion without any brushing where the results obtained prove to be more significant if the immersion period is seven days
S-adenosyl-L-methionine protects the liver against the cholestatic, cytotoxic, and vasoactive effects of leukotriene D4: a study with isolated and perfused rat liver
Cysteinyl-leukotrienes can cause cholestasis and liver damage when administered at nanomolar concentrations. Using the isolated and perfused rat liver we analyzed whether S-adenosyl-L-methionine (SAMe) may protect this organ against the noxious effects of leukotriene-D4 (LTD4). We observed that a 2 nmol bolus of this compound decreased bile flow (-12.6% +/- 1.6%, P < .02), and bile salt excretion (-23.5% +/- 2.2%, P < .02; both compared with baseline values), caused the release of glutamic-oxaloacetic transaminase (GOT) and lactic dehydrogenase (LDH) to the hepatic effluent, and increased significantly the perfusion pressure as compared with a control group not receiving LTD4 (6.0 +/- 1.1 vs. 0.2 +/- 0.02 mm hg, respectively; P < .001). The cholestatic effect of LTD4 was attenuated by infusion of SAMe which, at rates of 67 and 100 microg/min, totally prevented the decrease in bile salt excretion. Likewise, in SAMe infused livers, the release to the effluent of GOT and LDH was lower than in the group receiving LTD4 only, and was even lower than in the control group. We also found that the increase in perfusion pressure induced by LTD4 was prevented by SAMe in a dose-dependent manner. Of interest, SAMe increased the biliary excretion of the eicosanoid in a dose-related fashion. We conclude that SAMe reverts the cholestatic, cytotoxic, and hemodynamic effects of LTD4 on the liver, and that these protective effects might be partly because of a stimulation of the biliary excretion of the leukotriene
The cirrhotic liver is depleted of docosahexaenoic acid (DHA), a key modulator of NF-κB and TGFβ pathways in hepatic stellate cells
Liver cirrhosis results from chronic hepatic damage and is characterized by derangement of the organ architecture
with increased liver fibrogenesis and defective hepatocellular function. It frequently evolves into progressive hepatic
insufficiency associated with high mortality unless liver transplantation is performed. We have hypothesized that the
deficiency of critical nutrients such as essential omega-3 fatty acids might play a role in the progression of liver
cirrhosis. Here we evaluated by LC-MS/MS the liver content of omega-3 docosahexaenoic fatty acid (DHA) in cirrhotic
patients and investigated the effect of DHA in a murine model of liver injury and in the response of hepatic stellate
cells (HSCs) (the main producers of collagen in the liver) to pro-fibrogenic stimuli. We found that cirrhotic livers exhibit
a marked depletion of DHA and that this alteration correlates with the progression of the disease. Administration of
DHA exerts potent anti-fibrogenic effects in an acute model of liver damage. Studies with HSCs show that DHA inhibits
fibrogenesis more intensely than other omega-3 fatty acids. Data from expression arrays revealed that DHA blocks
TGFβ and NF-κB pathways. Mechanistically, DHA decreases late, but not early, SMAD3 nuclear accumulation and
inhibits p65/RelA-S536 phosphorylation, which is required for HSC survival. Notably, DHA increases ADRP expression,
leading to the formation of typical quiescence-associated perinuclear lipid droplets. In conclusion, a marked depletion
of DHA is present in the liver of patients with advanced cirrhosis. DHA displays anti-fibrogenic activities on HSCs
targeting NF-κB and TGFβ pathways and inducing ADPR expression and quiescence in these cells
Prognostic model for early acute rejection after liver transplantation
Hepatic graft rejection is a common complication after liver transplantation
(LT), with a maximum incidence within the first weeks. The identification of
high-risk patients for early acute rejection (EAR) might be useful for
clinicians. A series of 133 liver graft recipients treated with calcineurin
inhibitors was retrospectively assessed to identify predisposing factors for EAR
and develop a mathematical model to predict the individual risk of each patient.
The incidence of EAR (< or =45 days after LT) was 35.3%. Multivariate analysis
showed that recipient age, underlying liver disease, and Child's class before LT
were independently associated with the development of EAR. Combining these 3
variables, the following risk score for the development of EAR was obtained: EAR
score [F(x)] = 2.44 + (1.14 x hepatitis C virus cirrhosis) + (2.78 x immunologic
cirrhosis) + (2.51 x metabolic cirrhosis)--(0.08 x recipient age in years) +
(1.65 x Child's class A) [corrected]. Risk for rejection = e(F(x))/1 + e(F(x)).
The combination of age, cause of liver disease, and Child's class may allow us to
predict the risk for EAR
La evolución y la dinámica de las centrales de compra en Colombia
Teniendo en cuenta que cada día la manera de vivir y todos los aspectos que esto conlleva cambian, se hace importante destacar la evolución y dinámica de las centrales de compra en Colombia, porque si bien es cierto que no cambia el principio de satisfacer las necesidades básicas de cada persona, sí cambia la manera como se logra. Por esta razón este artículo muestra la evolución de las tiendas de barrio con la entrada de las cadenas de almacenes como Éxito, Carrefour entre otras al país, la evolución se ha venido dando gracias a los procedimientos y exigencias en el servicio y lo podemos entender en los precios, calidad y disponibilidad de los productos
Liver transplantation in cirrhotic patients with diabetes mellitus: Midterm results, survival, and adverse events
Liver cirrhosis is frequently associated with diabetes mellitus (DM), and this
metabolic complication is also frequent after orthotopic liver transplantation
(OLT). The aim of our study is to investigate which factors are associated with
DM before and after OLT and their impact on post-OLT evolution. We evaluated the
prevalence of DM among 115 liver transplant candidates with cirrhosis and
assessed their evolution after OLT (median follow-up, 41 months). Sixteen
candidates had DM requiring pharmacological therapy (group A), 45 candidates had
DM controlled with diet (group B), and 54 candidates did not have DM (group C).
One-year and 3-year actuarial survival rates were 100% and 100% for group A, 91%
and 85% for group B, and 77% and 74% for group C, respectively (P <.03). Post-OLT
DM was more frequent in group A. The incidence of other metabolic complications,
major infections, rejection, and arterial hypertension; the need for
hospitalization; and renal and graft function of patients in groups A, B, and C
were similar. The only risk factor for DM 1 year after OLT on multivariate
analysis was pre-OLT DM requiring pharmacological treatment. The incidence of
complications, need for hospitalization, and renal and graft function 1 year
after OLT for patients with post-OLT DM were similar to those of patients without
post-OLT DM. In conclusion, patients with cirrhosis who have DM have a greater
risk for post-OLT DM, but their midterm survival is not worse than the survival
of those without DM
Specialized pro-resolving mediators prevents cardiac dysfunction by modulating Ca2+ handling and NRF2 axis
Trabajo presentado en el ESC Congress 2021 - The Digital Experience, celebrado en modalidad virtual el 27 de agosto de 2021
EPIC 219388192 b - an inhabitant of the brown dwarf desert in the Ruprecht 147 open cluster
We report the discovery of EPIC 219388192 b, a transiting brown dwarf in a
5.3-day orbit around a member star of Ruprecht-147, the oldest nearby open
cluster association, which was photometrically monitored by K2 during its
Campaign 7. We combine the K2 time-series data with ground-based adaptive
optics imaging and high resolution spectroscopy to rule out false positive
scenarios and determine the main parameters of the system. EPIC 219388192 b has
a radius of =~ and mass of
=~, yielding a mean density of
~. The host star is nearly a Solar twin with
mass =~, radius
=~, effective temperature
=~K and iron abundance [Fe/H]=~dex.
Its age, spectroscopic distance, and reddening are consistent with those of
Ruprecht-147, corroborating its cluster membership. EPIC 219388192 b is the
first brown dwarf with precise determinations of mass, radius and age, and
serves as benchmark for evolutionary models in the sub-stellar regime.Comment: 13 pages, 11 figures, 4 tables, submitted to AAS Journal
Tratamiento de la cirrosis biliar primaria con ácido ursodesoxicólico. Resultados a corto y medio plazo y relación con el estudio de la enfermedad
We present the results of the treatment with ursodeoxycholic acid (UDCA, 7-9 mg/kg body weight daily) of 17 patients with primary biliary cirrhosis (8 in stages I-II; 9 in stages III-IV). At two months the mean values of alkaline phosphatase, gammaglutamiltranspeptidase, alanine and aspartate aminotransferase were reduced (p less than 0.001, p less than 0.001, p less than 0.01 and p less than 0.01 respectively). This improvement persisted without increase during the first year. At two months the total bilirubin value was reduced (p less than 0.01) associated with a reduction in the conjugated fraction (p less than 0.05). Cholesterol and gammaglobulin mean values also decreased at two months (p less than 0.05). We found no changes in IgM levels and antimitochondrial antibody titers. The improvement was similar in both groups (early I-II and advanced III-IV stages) and the treatment showed no undesirable effects either in early or advanced stages. Almost all the patients with pruritus (6 out of 7) improved with the treatment and the use of cholestyramine was reduced in al
- …