1,257 research outputs found
Indirect Effects of Pesticide Regulation and the Food Quality Protection Act
A driving factor behind pesticide regulation in Canada and the United States is the desire to protect consumers from harmful residues on food. The Food Quality Protection Act (FQPA) was unanimously passed by the U.S. Congress in 1996 and hailed as a landmark piece of pesticide legislation. It amended the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Federal Food, Drug, and Cosmetic Act (FFDCA), and focused on new ways to determine and mitigate the adverse health effects of pesticides. The FQPA is different from past legislation; it is based on the understanding that pesticides can have cumulative effects on people and that policy should be designed to protect the most vulnerable segments of the population. Recent research has investigated some of the impacts the FQPA’s provisions – many of which have yet to be fully implemented – may have on growers and consumers.Agricultural and Food Policy,
More evidence for extinction of activity in galaxies
This Research Note amends an article in which we showed that radio-loud
quasars can become radio-quiet. Exploring the analogy between galactic nuclei
and X-ray binaries (XRB), we pointed out there that this transition in quasars
could be identified with a switch from low/hard to high/soft state in
microquasars. Here, we present the evidence that traces of past occurrences of
this kind of phenomena can be found in normal but once active galaxies. Based
on the properties of a few such "post-active" galaxies that are representative
for a much wider group, it has been argued that they have reached the
evolutionary stages when their nuclei, which were radio-loud in the past, now,
mimicking the behaviour of XRBs, remain in the intermediate state on their way
towards quiescence or even have already entered the quiescent state. It follows
that the full evolutionary track of XRBs can be mapped onto the evolution of
galaxies. The above findings are in line with those reported recently for IC
2497, a galaxy that 70,000 years ago or less hosted a quasar but now appears as
a normal one. This scenario stems from the presence of Hanny's Voorwerp, a
nebulous object in its vicinity excited by that QSO in the epoch when IC 2497
was active. The post-active galaxies we deal with here are accompanied by
extremely weak and diffuse relic radio lobes that were inflated during their
former active period. These relics can be regarded as radio analogues of
Hanny's Voorwerp.Comment: 10 pages, 6 figures, A&A in pres
Ventricular longitudinal function is associated with microvascular obstruction and intramyocardial haemorrhage.
Microvascular obstruction (MVO) and intramyocardial haemorrhage (IMH) are associated with adverse prognosis, independently of infarct size after reperfused ST-elevation myocardial infarction (STEMI). Mitral annular plane systolic excursion (MAPSE) is a well-established parameter of longitudinal function on echocardiography.We aimed to investigate how acute MAPSE, assessed by a four-chamber cine-cardiovascular MR (CMR), is associated with MVO, IMH and convalescent left ventricular (LV) remodelling.54 consecutive patients underwent CMR at 3T (Intera CV, Philips Healthcare, Best, The Netherlands) within 3 days of reperfused STEMI. Cine, T2-weighted, T2* and late gadolinium enhancement (LGE) imaging were performed. Infarct and MVO extent were measured from LGE images. The presence of IMH was investigated by combined analysis of T2w and T2* images. Averaged-MAPSE (medial-MAPSE+lateral-MAPSE/2) was calculated from 4-chamber cine imaging.44 patients completed the baseline scan and 38 patients completed 3-month scans. 26 (59%) patients had MVO and 25 (57%) patients had IMH. Presence of MVO and IMH were associated with lower averaged-MAPSE (11.7±0.4 mm vs 9.3±0.3 mm; p<0.001 and 11.8±0.4 mm vs 9.2±0.3 mm; p<0.001, respectively). IMH (β=-0.655, p<0.001) and MVO (β=-0.567, p<0.001) demonstrated a stronger correlation to MAPSE than other demographic and infarct characteristics. MAPSE ≤10.6 mm demonstrated 89% sensitivity and 72% specificity for the detection of MVO and 92% sensitivity and 74% specificity for IMH. LV remodelling in convalescence was not associated with MAPSE (AUC 0.62, 95% CI 0.44 to 0.77, p=0.22).Postreperfused STEMI, LV longitudinal function assessed by MAPSE can independently predict the presence of MVO and IMH
Diabetes mellitus, microalbuminuria, and subclinical cardiac disease: Identification and monitoring of individuals at risk of heart failure
Background-Patients with type 2 diabetes mellitus and elevated urinary albumin:creatinine ratio (ACR) have increased risk of heart failure. We hypothesized this was because of cardiac tissue changes rather than silent coronary artery disease. Methods and Results-In a case-controlled observational study 130 subjects including 50 ACR+ve diabetes mellitus patients with persistent microalbuminuria (ACR > 2.5 mg/mol in males and > 3.5 mg/mol in females, ≥2 measurements, no previous renin- angiotensin-aldosterone therapy, 50 ACR-ve diabetes mellitus patients and 30 controls underwent cardiovascular magnetic resonance for investigation of myocardial fibrosis, ischemia and infarction, and echocardiography. Thirty ACR+ve patients underwent further testing after 1-year treatment with renin-angiotensin-aldosterone blockade. Cardiac extracellular volume fraction, a measure of diffuse fibrosis, was higher in diabetes mellitus patients than controls (26.1±3.4% and 23.3±3.0% P=0.0002) and in ACR+ve than ACR-ve diabetes mellitus patients (27.2±4.1% versus 25.1±2.9%, P=0.004). ACR+ve patients also had lower E0 measured by echocardiography (8.2±1.9 cm/s versus 8.9±1.9 cm/s, P=0.04) and elevated high-sensitivity cardiac troponin T 18% versus 4% ≥14 ng/L (P=0.05). Rate of silent myocardial ischemia or infarction were not influenced by ACR status. Renin-angiotensin-aldosterone blockade was associated with increased left ventricular ejection fraction (59.3±7.8 to 61.5±8.7%, P=0.03) and decreased extracellular volume fraction (26.5±3.6 to 25.2±3.1, P=0.01) but no changes in diastolic function or high-sensitivity cardiac troponin T levels. Conclusions-Asymptomatic diabetes mellitus patients with persistent microalbuminuria have markers of diffuse cardiac fibrosis including elevated extracellular volume fraction, high-sensitivity cardiac troponin T, and diastolic dysfunction, which may in part be reversible by renin-angiotensin-aldosterone blockade. Increased risk in these patients may be mediated by subclinical changes in tissue structure and function
Arabidopsis RecQl4A suppresses homologous recombination and modulates DNA damage responses
The DNA damage response and DNA recombination are two interrelated mechanisms involved in maintaining the integrity of the genome, but in plants they are poorly understood. RecQ is a family of genes with conserved roles in the regulation of DNA recombination in eukaryotes; there are seven members in Arabidopsis. Here we report on the functional analysis of the Arabidopsis RecQl4A gene. Ectopic expression of Arabidopsis RecQl4A in yeast RecQ-deficient cells suppressed their hypersensitivity to the DNA-damaging drug methyl methanesulfonate (MMS) and enhanced their rate of homologous recombination (HR). Analysis of three recQl4A mutant alleles revealed no obvious developmental defects or telomere deregulation in plants grown under standard growth conditions. Compared with wild-type Arabidopsis, the recQl4A mutant seedlings were found to be hypersensitive to UV light and MMS, and more resistant to mitomycin C. The average frequency of intrachromosomal HR in recQl4A mutant plants was increased 7.5-fold over that observed in wild-type plants. The data reveal roles for Arabidopsis RecQl4A in maintenance of genome stability by modulation of the DNA damage response and suppression of HR.
The transition from quasar radio-loud to radio-quiet state in the framework of the black hole scalability hypothesis
There are several lines of evidence that active galactic nuclei (AGN) can be
regarded as scaled-up X-ray binaries (XRB). The timescales of the evolutionary
phenomena in these two classes are proportional to the black hole (BH) masses.
Consequently, unlike in the case of XRBs, the evolution of AGNs is too slow to
be followed directly. What could be done, however, is to assign particular
types of active galaxies to different evolutionary stages observable in XRBs.
We studied such an assignment for three quasars with clear signatures of a
recent transition from the radio-loud to the radio-quiet state. The quasars we
investigated have large-scale radio lobes that are clearly asymmetric -- one
lobe is of Fanaroff-Riley II type, while the other one is a diffuse relic
devoid of a hotspot. We suggest that the prime cause of the asymmetry of these
radio sources is that the nuclei of their host galaxies currently produce no
jets. To prove that, we observed them with milliarcsecond resolution to check
if they are similar to those in radio-quiet quasars. The observations carried
out with the EVN revealed that the nuclei of the quasars under investigation
are not of a core-jet type that is characteristic for radio-loud,
lobe-dominated quasars. It follows that the lobes are no longer fuelled and
that the apparent asymmetry results from the orientation, which causes a time
lag of the order of 10^6 years between their images: the lobe perceived as a
relic is nearer than the lobe with a hotspot and so it is observed in a later
stage of the decay. The three AGNs under investigation were radio-loud earlier,
but now they have switched to the radio-quiet state. In the framework of the
XRB/AGN unification, the above means that they have left the very high state
and have moved now to the high/soft state. (abridged)Comment: 8 pages, 4 figures, A&A in pres
Athletic Cardiac Adaptation in Males Is a Consequence of Elevated Myocyte Mass.
Cardiac remodeling occurs in response to regular athletic training, and the degree of remodeling is associated with fitness. Understanding the myocardial structural changes in athlete's heart is important to develop tools that differentiate athletic from cardiomyopathic change. We hypothesized that athletic left ventricular hypertrophy is a consequence of increased myocardial cellular rather than extracellular mass as measured by cardiovascular magnetic resonance.Forty-five males (30 athletes and 15 sedentary age-matched healthy controls) underwent comprehensive cardiovascular magnetic resonance studies, including native and postcontrast T1 mapping for extracellular volume calculation. In addition, the 30 athletes performed a maximal exercise test to assess aerobic capacity and anaerobic threshold. Participants were grouped by athleticism: untrained, low performance, and high performance (O2max 60 mL/kg per min, respectively). In athletes, indexed cellular mass was greater in high- than low-performance athletes 60.7±7.5 versus 48.6±6.3 g/m(2); P<0.001), whereas extracellular mass was constant (16.3±2.2 versus 15.3±2.2 g/m(2); P=0.20). Indexed left ventricular end-diastolic volume and mass correlated with O2max (r=0.45, P=0.01; r=0.55, P=0.002) and differed significantly by group (P=0.01; P<0.001, respectively). Extracellular volume had an inverse correlation with O2max (r=-0.53, P=0.003 and left ventricular mass index (r=-0.44, P=0.02).Increasing left ventricular mass in athlete's heart occurs because of an expansion of the cellular compartment while the extracellular volume becomes relatively smaller: a difference which becomes more marked as left ventricular mass increases. Athletic remodeling, both on a macroscopic and cellular level, is associated with the degree of an individual's fitness. Cardiovascular magnetic resonance ECV quantification may have a future role in differentiating athlete's heart from change secondary to cardiomyopathy
Bacteriological studies of blood, tissue fluid, lymph and lymph nodes in patients with acute dermatolymphangioadenitis (DLA) in course of ‘filarial’ lymphedema
Filarial lymphedema is complicated by frequent episodes of dermatolymphangioadenitis (DLA). Severe systemic
symptoms during attacks of DLA resemble those of septicemia. The question we asked was whether bacterial isolates
can be found in the peripheral blood of patients during the episodes of DLA. Out of 100 patients referred to us with
‘filarial’ lymphedema 14 displayed acute and five subacute symptoms of DLA. All were on admission blood
microfilariae negative but had a positive test in the past. Blood bacterial isolates were found in nine cases, four acute
(21%) and five subacute (26%). In 10 acute cases blood cultures were found negative. Six blood isolates belonged to
Bacilli, four to Cocci and one was Sarcina. To identify the sites of origin of bacterial dissemination, swabs taken from
the calf skin biopsy wounds and tissue fluid, lymph and lymph node specimens were cultured. Swabs from the calf
skin biopsy wound contained isolates in nine (47%) cases. They were Bacilli in nine, Cocci in three, Acinetobacter and
Erwinia in two cases. Tissue fluid was collected from 10 patients and contained Bacilli in four (40%) and
Staphylococci in three (30%). Lymph was drained in four patients and contained isolates in all samples (100%). They
were Staphylococcus epidermis, xylosus and aureus, Acinetobacter, Bacillus subtilis and Sarcina. Three lymph nodes
were biopsied and contained Staphylococcus chromogenes, xylosus, Enterococcus and Bacillus cereus. In six cases the
same phenotypically defined species of bacteria were found in blood and limb tissues or fluids. In the ‘control’ group of patients with lymphedema without acute or subacute changes all blood cultures were negative. Interestingly, swabs
from biopsy wound of these patients contained isolates in 80%, tissue fluid in 68%, lymph in 70% and lymph nodes
in 58% of cases. In healthy controls, tissue fluid did not contain bacteria, and lymph isolates were found only in 12%
of cases. This study demonstrates that patients with acute episodes of DLA reveal bacteriemia in a high percentage
of cases. Diversity of blood and tissue bacterial isolates in these patients points to a breakdown of the skin immune
barrier in lymphedema and subsequently indiscriminate bacterial colonization of deep tissues and spread to an blood
circulation. © 1999 Elsevier Science B.V. All rights reserved
A novel and practical screening tool for the detection of silent myocardial infarction in patients with type 2 diabetes
Silent myocardial infarction (MI) is a prevalent finding in patients with type 2 diabetes and is associated with significant mortality and morbidity. Late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) is the most validated technique for detection of silent MI but is time consuming, costly and requires administration of intravenous contrast. We therefore planned to develop a simple and low cost population screening tool to identify those at highest risk of silent MI validated against the CMR reference standard.100 asymptomatic patients with type 2 diabetes underwent electrocardiogram (ECG), echocardiography, biomarker assessment and CMR at 3.0T including assessment of left ventricular ejection fraction and LGE. Global longitudinal strain (GLS) from 2 and 4 chamber cines was measured using feature tracking.17/100 patients with no history of cardiovascular disease had silent MI defined by LGE in an infarct pattern on CMR. Only 4 silent MI patients had Q waves on ECG. Patients with silent MI were older (65 vs 60, p=0.05), had lower E/A ratio (0.75 vs 0.89, p=0.004), lower GLS (-15.2% vs -17.7%, p=0.004) and higher NT-proBNP (106ng/L vs 52ng/L, p=0.003). A combined risk score derived from these 4 factors had an area under the receiver operating characteristic (ROC) curve of 0.823 (0.734-0.892), P<0.0001. A score of ?3/5 had 82% sensitivity and 72% specificity for silent MI.Using measures that can be derived in an outpatient clinic setting, we have developed a novel screening tool for the detection of silent MI in type 2 diabetes. The screening tool had significantly superior diagnostic accuracy than current ECG criteria for the detection of silent MI in asymptomatic patients
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