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A study was conducted to investigate whether increased levels of nonfasting triglycerides are associated with a risk of ischemic stroke amongst the general population.

In vitro, [alpha]-adrenoreceptor stimulation of rat mesenteric small arteries often leads to a rhythmic change in wall tension, i.e., vasomotion. Within the individual smooth muscle cells of the vascular wall, vasomotion is often preceded by a period of asynchronous calcium waves. Abruptly, these low-frequency waves may transform into high-frequency whole cell calcium oscillations. Simultaneously, multiple cells synchronize, leading to rhythmic generation of tension. We present a mathematical model of vascular smooth muscle cells that aims at characterizing this sudden transition. Simulations show calcium waves sweeping through the cytoplasm when the sarcoplasmic reticulum (SR) is stimulated to release calcium. A rise in cGMP leads to the experimentally observed transition from waves to whole cell calcium oscillations. At the same time, membrane potential starts to oscillate and the frequency approximately doubles. In this transition, the simulated results point to a key role for a recently discovered cGMP-sensitive calcium-dependent chloride channel. This channel depolarizes the membrane in response to calcium released from the SR. In turn, depolarization causes a uniform opening of L-type calcium channels on the cell surface, stimulating a synchronized release of SR calcium and inducing the shift from waves to whole cell oscillations. The effect of the channel is therefore to couple the processes of the SR with those of the membrane. We hypothesize that the shift in oscillatory mode and the associated onset of oscillations in membrane potential within the individual cell may underlie sudden intercellular synchronization and the appearance of vasomotion. vasomotion; mesenteric arteries; mathematical model doi:10.1152/ajpheart.00726.2006

Vasomotion is a rhythmic variation in microvascular diameter. Although known for more than 150 years, the cellular processes underlying the initiation of vasomotion are not fully understood. In the present study a model of a single cell is extended by coupling a number of cells into a tube. The simulated results point to a permissive role of cGMP in establishing intercellular synchronization. In sufficient concentration, cGMP may activate a cGMP-sensitive calcium-dependent chloride channel, causing a tight spatiotemporal coupling between release of sarcoplasmic reticulum calcium, membrane depolarization, and influx of extracellular calcium. Low [cGMP] is associated only with unsynchronized waves. At intermediate concentrations, cells display either waves or whole cell oscillations, but these remain unsynchronized between cells. Whole cell oscillations are associated with rhythmic variation in membrane potential and flow of current through gap junctions. The amplitude of these oscillations in potential grows with increasing [cGMP], and, past a certain threshold, they become strong enough to entrain all cells in the vascular wall, thereby initiating sustained vasomotion. In this state there is a rhythmic flow of calcium through voltage-sensitive calcium channels into the cytoplasm, making the frequency of established vasomotion sensitive to membrane potential. It is concluded that electrical coupling through gap junctions is likely to be responsible for the rapid synchronization across a large number of cells. Gap-junctional current between cells is due to the appearance of oscillations in the membrane potential that again depends on the entrainment of sarcoplasmic reticulum and plasma membrane within the individual cell. vasomotion; mathematical model; chloride channel; gap junctions doi:10.1152/ajpheart.00727.2006

The article presents a study that investigates on the impact of missense polymorphisms in BRCA1 and BRCA2 on the risk of breast and ovarian cancer. It states that nine possible biologically relevant polymorphisms were identified from 194 women with familial history of breast or ovarian cancer. It was concluded that heterozygosity and homozygosity of the examined nine missense polymophisms cannot explain the increased risk of breast and ovarian cancer in families with hereditary condition.

Abstract: Ischemic cardiovascular disease and obstructive pulmonary disease involve inflammation. Leukotrienes may be important pro-inflammatory mediators. We tested the hypothesis that the (-1072)G>A and (-444)A>C promoter polymorphisms of leukotriene C4 synthase confer risk of transient ischemic attack (TIA), ischemic stroke, ischemic heart disease (IHD), asthma, and chronic obstructive pulmonary disease (COPD). We genotyped individuals from the Danish general population, the Copenhagen City Heart Study, and Danish patients with IHD/coronary atherosclerosis, the Copenhagen Ischemic Heart Disease Study. We used prospective (n =10,386), cross-sectional (n =10,386), and case-control (n =2392+5012) designs. Allele frequency was 0.07 for (-1072)A and 0.29 for (-444)C. Cumulative incidence for TIA was higher for (-1072)AA versus GG genotype (log-rank: p <0.001), and lower for (-444)CC versus AA genotype (log-rank: p =0.03). Cumulative incidence for ischemic stroke was also lower for (-444)CC versus AA genotype (log-rank: p =0.04). Multifactorially adjusted hazard ratios for TIA were 5.2(95% CI:1.9–14) for (-1072)AA versus GG genotype, and 0.4(0.2–1.0) for (-444)CC versus AA genotype. Corresponding values were 1.9 (0.7–5.2) and 0.7 (0.5–1.0) for ischemic stroke, and 0.8 (0.4–1.6) and 1.0 (0.9–1.2) for IHD. In the case-control study, corresponding multifactorially adjusted odds ratios for IHD/coronary atherosclerosis were 0.5 (0.2–1.3) and 1.2 (1.0–1.5). These genotypes were not associated with risk of asthma or COPD. Leukotriene C4 synthase promoter genotypes influence risk of TIA and ischemic stroke, but not risk of IHD/coronary atherosclerosis, asthma, or COPD. [Copyright &y& Elsevier]

Illusions of self-motion (vection) can provide compelling sensations of moving through virtual environments without the need for complex motion simulators or large tracked physical walking spaces. Here we explore the interaction between biomechanical cues (stepping along a rotating circular treadmill) and visual cues (viewing simulated self-rotation) for providing stationary users a compelling sensation of rotational self-motion (circular vection). When tested individually, biomechanical and visual cues were similarly effective in eliciting self-motion illusions. However, in combination they yielded significantly more intense self-motion illusions. These findings provide the first compelling evidence that walking motions can be used to significantly enhance visually induced rotational self-motion perception in virtual environments (and vice versa) without having to provide for physical self-motion or motion platforms. This is noteworthy, as linear treadmills have been found to actually impair visually induced translational self-motion perception (Ash, Palmisano, Apthorp, & Allison, 2013). Given the predominant focus on linear walking interfaces for virtual-reality locomotion, our findings suggest that investigating circular and curvilinear walking interfaces offers a promising direction for future research and development and can help to enhance self-motion illusions, presence and immersion in virtual-reality systems., (© 2015 ARVO.)

Introduction: We tested the hypothesis that individuals in the general population with and without ischaemic cardiovascular disease, or with diabetes, are treated to recommended target values for plasma lipids., Material and Methods: We used the Copenhagen General Population Study in which 69,354 individuals were examined cross-sectionally from 2004 through 2010. Among this population, 1,521 had previously had myocardial infarction, 2,372 other ischaemic heart disease, 542 ischaemic stroke, 2,086 claudicatio intermittens and 2,155 had diabetes., Results: The fraction of participants using lipid-lowering therapy among those with myocardial infarction was 70%, other ischaemic heart disease 44%, ischaemic stroke 60%, claudicatio intermittens 33%, diabetes 48%, and for those without ischaemic cardiovascular disease 8%. Among those with myocardial infarction with and without lipid-lowering therapy, 41% and 84%, respectively, had not reached a total cholesterol < 4.5 mmol/l, 30% and 79%, respectively, had not reached a low-density lipoprotein cholesterol < 2.5 mmol/l, and 46% and 48%, respectively, had not reached triglycerides < 1.7 mmol/l. In those with other ischaemic cardiovascular disease, with diabetes or without ischaemic cardiovascular disease, a similar or larger fraction of individuals did not reach guideline lipid targets., Conclusion: Large fractions of individuals with ischaemic cardiovascular disease or diabetes are not treated with lipid-lowering therapy. Even among many of those treated, plasma total cholesterol, low-density lipoprotein cholesterol and triglycerides are not treated to guideline targets.

Non-fasting triglycerides are measured at any time within up to 8 h (14 h) after any normal meal, while postprandial triglycerides are measured at a fixed time point within up to 8 h (14 h) of a standardised fat tolerance test. The simplest possible way of evaluating remnant cholesterol is non-fasting/postprandial total cholesterol minus low-density lipoprotein (LDL) cholesterol minus high-density lipoprotein (HDL) cholesterol. Elevated levels of non-fasting/postprandial triglycerides directly correlate with elevated remnant cholesterol. In the general population, 38% of men have non-fasting/postprandial triglycerides > 2mmol/L (>176 mg/dL) while 45% of men have non-fasting/postprandial triglyceride levels of 1-2 mmol/L (89-176 mg/dL); corresponding fractions in women are 20% and 47%. Also, 31% of men have remnant cholesterol levels > 1mmol/L (>39 mg/dL) while 46% of men have remnant cholesterol levels of 0.5-1 mmol/L (19-39 mg/dL); corresponding fractions in women are 15% and 43%. Non-fasting triglycerides ≥5 mmol/L vs. <1 mmol/L marked a 17 and 5 fold increased risk of myocardial infarction, a 5 and 3 fold increased risk of ischemic stroke, and a 4 and 2 fold increased risk of early death in women and men in the general population. As all cells can degrade triglycerides it is biologically unlikely that it is the triglyceride molecules themselves that cause atherosclerosis and cardiovascular disease. However, elevated remnant cholesterol may lead to cholesterol entrapment in the arterial intima and consequently to accelerated atherosclerosis and cardiovascular disease.

Purpose: BRCA1 and BRCA2 are key tumor suppressors with a role in cellular DNA repair, genomic stability, and checkpoint control. Mutations in BRCA1 and BRCA2 often cause hereditary breast and ovarian cancer; however, missense polymorphisms in these genes pose a problem in genetic counseling, as their impact on risk of breast and ovarian cancer is unclear., Experimental Design: We resequenced BRCA1 and BRCA2 in 194 women with a familial history of breast and/or ovarian cancer and identified nine possibly biologically relevant polymorphisms (BRCA1 Gln356Arg, Pro871Leu, Glu1038Gly, Ser1613Gly, and Met1652Ile. BRCA2 Asn289His, Asn372His, Asp1420Tyr, and Thr1915Met). [corrected] We evaluated risk of breast and/or ovarian cancer by these polymorphisms in a prospective study of 5,743 women from the general population followed for 39 years and in a case-control study of 1,201 breast cancer cases and 4,120 controls., Results: We found no association between heterozygosity or homozygosity for any of the nine polymorphisms and risk of breast and/or ovarian cancer in either study. We had 80% power to exclude hazard/odds ratios for heterozygotes and/or homozygotes for all nine missense polymorphisms above 1.3 to 3.3 in the prospective study, and above 1.2 to 3.2 in the case-control study., Conclusions: Heterozygosity and homozygosity of any of the examined nine BRCA1 and BRCA2 missense polymorphisms cannot explain the increased risk of breast and/or ovarian cancer observed in families with hereditary breast and/or ovarian cancer. Therefore, genetic counseling of such families safely can disregard findings of these missense polymorphisms.

The role of triglycerides in the risk of ischemic stroke remains controversial. We tested the hypothesis that increased levels of nonfasting triglycerides are associated with ischemic stroke in the general population. Men with a nonfasting triglyceride level 5 mmol/l had a multivariable, adjusted hazard ratio for ischemic stroke of 2.5 (95% confidence interval: 1.3-4.8) compared with men with a nonfasting triglyceride level < 1 mmol/l. The corresponding value in women was 3.8 (1.3-11). We conclude that the level of nonfasting triglycerides is associated with risk of ischemic stroke.

We tested the hypotheses that lipid levels change minimally in response to normal food intake and that nonfasting levels predict cardiovascular events. The maximum changes after normal food intake from fasting levels were as follows: total cholesterol -0.2 mmol/l, LDL cholesterol -0.2 mmol/l, HDL cholesterol -0.1 mmol/l, and for triglycerides +0.3 mmol/l. Highest versus lowest tertile of nonfasting total cholesterol, LDL cholesterol, and triglycerides, and lowest versus highest tertile of nonfasting HDL cholesterol predicted a 1.7-to 2.2-fold increased risk of cardiovascular events.

Objective: Cysteinyl leukotrienes are involved in inflammation and possibly in early carotid atherosclerosis. We tested the hypothesis that the -444 A/C and -1072 G/A polymorphisms of the leukotriene C(4) synthase associate with risk of ischemic cerebrovascular disease., Methods and Results: We genotyped 10 592 individuals from the Danish general population, the Copenhagen City Heart Study. During 24 years of follow-up, 557 individuals developed ischemic cerebrovascular disease. The allele frequency was 0.07 for -1072 A and 0.29 for -444 C. Cumulative incidence for ischemic cerebrovascular disease was higher for -1072 AA versus GG genotype (log-rank: P=0.002), and lower for -444 CC versus AA genotype (log-rank: P=0.008). Combined genotypes showed corresponding cumulative incidence differences (log-rank: P=0.003). Multifactorially adjusted hazard ratios for ischemic cerebrovascular disease were 2.8(1.4 to 5.7) for -1072 AA versus GG genotype, 0.6(0.4 to 0.9) for -444 CC versus AA genotype, 2.5(1.2 to 5.4) for combined AA-AA versus GG-AA genotype, and 0.6(0.4 to 0.9) for combined GG-CC versus GG-AA genotype. Genotype did not associate with risk of deep venous thrombosis or severe carotid atherosclerosis, or with levels of platelets and coagulation factors., Conclusions: Leukotriene C(4) synthase -1072 AA genotype predict increased risk, whereas -444 CC genotype predict decreased risk of ischemic cerebrovascular disease.