Angina at Low heart rate And Risk of imminent Myocardial infarction (the ALARM study): a prospective, observational proof-of-concept study.

BACKGROUND: Myocardial infarction (MI) is often preceded by unstable angina. Helping patients identify the onset of unstable angina rather than MI may result in earlier treatment and improve outcomes. Unstable angina is angina occurring at a lower-than-usual workload. Since heart rate (HR) is correlated with degree of exertion, we hypothesised that angina occurring at low HR is a warning signal for unstable angina and MI. METHODS: In this prospective study, 111 patients with acute coronary syndrome (ACS) or prognostically significant coronary disease were recruited. Each patient's HR was measured using a portable electrocardiogram (ECG) recorder after regular class III exercise on the Canadian Cardiovascular Society Angina Grading Scale and the cumulative moving average and three-sigma (standard deviation) range were calculated for each new measurement. The HR was subsequently measured at the beginning of angina; a HR lower than the preceding three-sigma ranges for class III or anginal HR was regarded as a 'warning signal'. The proportion of warning signals associated with ACS occurring in the following 2 weeks was compared with that for non-warning signals. RESULTS: Nine cases of ACS occurred in eight patients. Two cases were preceded by warning signals; a signal marked the onset of ACS in a third patient, and four patients failed to make anginal ECG recordings. There were 591 documented episodes of angina during the study and ECGs were available for 383 (64.8 %) of these of which 55 were warning signals. Of these warning signals, 4 occurred in the 2 weeks preceding ACS, compared with 4 of 328 non-warning signals (odds ratio, 6.4; 95 % confidence interval, 1.5-26.2; p = 0.01; positive predictive value, 7.3 %; negative predictive value, 98.8 %). CONCLUSIONS: Low HR angina may identify unstable angina and serve as an early warning for MI. In addition, angina that does not occur at a low heart rate indicates that ACS is very unlikely.

An audit comparing management of patients with HFrEF at a DGH before and during the COVID-19 pandemic.

This audit compared the management of patients with heart failure with reduced ejection fraction (HFrEF) admitted to a district general hospital (DGH) during comparative eight month periods before and during the COVID-19 pandemic. The periods studied were from 1st February 2019 to 30th September 2019 and between the same dates in 2020. We investigated differences in mortality and patient characteristics (age, gender and new or prior diagnosis). For patients who survived to discharge and who were not referred to palliative care, we also investigated whether there were differences in rates of echocardiography and prescription of angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor antagonists and beta blockers. We found that the number of cases was lower during the pandemic and there was a lower mortality rate that was not statistically significant. There was a higher proportion of new cases (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.24 to 3.94, p=0.008) and of female patients (OR 2.03, 95%CI 1.14 to 3.61, p=0.019). For survivors, there was a non-significant decrease in prescription rates for ACE inhibitors and angiotensin II receptor antagonists (81.6% vs. 71.4%, p=0.137) that was not seen for beta blockers. The length of stay was increased and there was also an increase in the interval between admission and echocardiography in patients who were newly diagnosed. Regardless of time period, the time before echocardiography was significantly associated with length of stay.

Efficient production of secretory Streptomyces clavuligerus ß-lactamase inhibitory protein (BLIP) in Pichia pastoris.

ß-Lactamase inhibitory protein (BLIP), a low molecular weight protein from Streptomyces clavuligerus, has a wide range of potential applications in the fields of biotechnology and pharmaceutical industry because of its tight interaction with and potent inhibition on clinically important class A ß-lactamases. To meet the demands for considerable amount of highly pure BLIP, this study aimed at developing an efficient expression system in eukaryotic Pichia pastoris (a methylotrophic yeast) for production of BLIP. With methanol induction, recombinant BLIP was overexpressed in P. pastoris X-33 and secreted into the culture medium. A high yield of ~ 300 mg/L culture secretory BLIP recovered from the culture supernatant without purification was found to be > 90% purity. The recombinant BLIP was fully active and showed an inhibition constant (Ki) for TEM-1 ß-lactamase (0.55 ± 0.07 nM) comparable to that of the native S. clavuligerus-expressed BLIP (0.5 nM). Yeast-produced BLIP in combination with ampicillin effectively inhibited the growth of ß-lactamase-producing Gram-positive Bacillus. Our approach of expressing secretory BLIP in P. pastoris gave 71- to 1200-fold more BLIP with high purity than the other conventional methods, allowing efficient production of large amount of highly pure BLIP, which merits fundamental science studies, drug development and biotechnological applications.

Genotypic effect of the -565C>T polymorphism in the ABCA1 gene promoter on ABCA1 expression and severity of atherosclerosis.

OBJECTIVE: Loss-of-function mutations of the ATP-binding cassette transporter A1 (ABCA1) gene cause Tangier disease, a rare genetic disorder with accumulation of lipid-laden macrophages and increased risk of atherosclerosis. Common variants of this gene may be a genetic factor for atherosclerosis in the general population. This study was performed to test the reported association between the -565C>T polymorphism and atherosclerosis severity and to investigate whether this variant per se had an effect on promoter activity of the ABCA1 gene. METHODS AND RESULTS: A cohort of patients with coronary atherosclerosis were genotyped for the -565C>T polymorphism. Logistic regression analyses showed that homozygotes of the -565T allele had greatest mean number of diseased coronary arteries, particular in nonsmokers. Real-time reverse-transcriptase polymerase chain reaction showed that in atherosclerotic plaques removed from patients undergoing endarteretomy, ABCA1 expression levels were lowest in those who had the T/T genotype and highest in those of the C/C genotype. Transfection and reporter assays demonstrated that in cultured macrophages, the -565T allelic promoter had a lower activity in driving gene expression than the -565C allelic promoter. Electrophoretic mobility shift assays displayed differential binding of nuclear proteins to the 2 alleles. CONCLUSIONS: These results indicate that the -565C>T polymorphism has an allele-specific effect on ABCA1 gene expression and provide further evidence of a genotypic effect on coronary atherosclerosis severity. The study showed that the ABCA1 gene -565C>T polymorphism was associated with severity of coronary atherosclerosis in a cohort of patients from Southern England and that this sequence variant per se had an effect on promoter activity of the ABCA1 gene. The data support the notion that common ABCA1 gene variants can contribute to interindividual variability in atherosclerosis susceptibility and severity.

Influences of matrix metalloproteinase-3 gene variation on extent of coronary atherosclerosis and risk of myocardial infarction.

OBJECTIVES: The aim of this study was to assess matrix metalloproteinase-3 (MMP3) gene variation in relation to the degree of coronary atherosclerosis and risk of myocardial infarction (MI) in patients with coronary artery disease. METHODS: In this study, we systematically screened the promoter and coding regions for sequence variants. All polymorphisms identified were analyzed in 1,240 individuals undergoing coronary angiography. Functional analyses of the polymorphisms were carried out with the use of report assays and electrophoretic mobility shift assays. RESULTS: Six novel polymorphisms were identified. The 6A/6A genotype was associated with greater number of coronary arteries with significant stenosis (odds ratio [OR] 1.52, p = 0.008), whereas the 5A/5A and 5A/6A genotypes were associated with increased risk of MI (OR 2.02 and 1.78, p = 0.016 and 0.032, respectively). A stepwise logistic regression analysis with all polymorphisms taken into account showed that the effect of MI susceptibility was largely attributed to the 5A/6A polymorphism. In a stepwise logistic regression analysis with all haplotypes as independent variables, the most common haplotype (T-5A-A-A-G-A), and two rare haplotypes, all containing the 5A allele, were associated with MI susceptibility. Functional studies showed that the T-5A-A-A-G-A haplotype had a higher promoter activity in macrophages. CONCLUSIONS: These data indicate that the effect of MMP3 gene variation is attributable to the 5A/6A polymorphism and that individuals carrying the 6A/6A genotype may be predisposed to developing atherosclerotic plaques with significant stenosis, whereas those carrying the 5A allele may be predisposed to developing unstable plaques.