Regulation of metabolism and proton motive force generation during mixed carbon fermentation by an Escherichia coli strain lacking the FOF1-ATPase.

Proton FOF1-ATPase is the key enzyme in E. coli under fermentative conditions. In this study the role of E. coli proton ATPase in the µ and formation of metabolic pathways during the fermentation of mixture of glucose, glycerol and formate using the DK8 (lacking FOF1) mutant strain was investigated. It was shown that the contribution of FOF1-ATPase in the specific growth rate was ∼45 %. Formate was not taken up in the DK8 strain during the initial hours of the growth. The utilization rates of glucose and glycerol were unchanged in DK8, however, the production of succinate, lactate and ethanol was decreased causing a reduction of the redox state up to -450 mV. Moreover, the contribution of FOF1-ATPase in the interplay between H+ and H2 cycles was described depending on the bacterial growth phase and main utilizing substrate. Besides, the H2 production rate in the DK8 strain was decreased by ∼60 % at 20 h and was absent at 72 h. Δp was decreased from -157 ± 4.8 mV to -140 ± 4.2 mV at 20 h and from -195 ± 5.9 mV to -148 ± 4.4 mV at 72 h, compared to WT. Taken together it can be concluded that during fermentation of mixed carbon sources metabolic cross talk between FOF1-ATPase-TrkA-Hyd-Fdh-H is taking place for maintaining the cell energy balance via regulation proton motive force.

Stereolithography of ceramic scaffolds for bone tissue regeneration: Influence of hydroxyapatite/silica ratio on mechanical properties.

In this paper, the results obtained in the development of ceramic resin feedstock for stereolithography are shown. Hydroxyapatite and silica are used as source of ceramic. Hydroxyapatite is extracted from bovine bone, which enhances bioactivity of ceramic scaffold. The influence of hydroxyapatite amount in polymer-based slurry on the viscosity and printability of feedstock is explored. Hydroxyapatite and silica containing scaffolds are successfully obtained by stereolithography. Influence of hydroxyapatite/silica ratio on the bioactivity, biodegradability and mechanical properties of the scaffolds is also studied. It was observed that higher concentrations of hydroxyapatite led to improved mechanical strength of the scuffolds but increased viscosity of the slurry, affecting printability. Cell viability assays and cell visualization experiments indicated that the scaffolds not cause significant cell toxicity.

COVID-19 and its impact on the cardiovascular system.

OBJECTIVES: The clinical impact of SARS-CoV-2 has varied across countries with varying cardiovascular manifestations. We review the cardiac presentations, in-hospital outcomes and development of cardiovascular complications in the initial cohort of SARS-CoV-2 positive patients at Imperial College Healthcare National Health Service Trust, UK. METHODS: We retrospectively analysed 498 COVID-19 positive adult admissions to our institute from 7 March to 7 April 2020. Patient data were collected for baseline demographics, comorbidities and in-hospital outcomes, especially relating to cardiovascular intervention. RESULTS: Mean age was 67.4±16.1 years and 62.2% (n=310) were male. 64.1% (n=319) of our cohort had underlying cardiovascular disease (CVD) with 53.4% (n=266) having hypertension. 43.2%(n=215) developed acute myocardial injury. Mortality was significantly increased in those patients with myocardial injury (47.4% vs 18.4%, p<0.001). Only four COVID-19 patients had invasive coronary angiography, two underwent percutaneous coronary intervention and one required a permanent pacemaker implantation. 7.0% (n=35) of patients had an inpatient echocardiogram. Acute myocardial injury (OR 2.39, 95% CI 1.31 to 4.40, p=0.005) and history of hypertension (OR 1.88, 95% CI 1.01 to 3.55, p=0.049) approximately doubled the odds of in-hospital mortality in patients admitted with COVID-19 after other variables had been controlled for. CONCLUSION: Hypertension, pre-existing CVD and acute myocardial injury were associated with increased in-hospital mortality in our cohort of COVID-19 patients. However, only a low number of patients required invasive cardiac intervention.

Multimodality imaging predictors of sudden cardiac death.

Sudden cardiac death (SCD) is the worst clinical event occurring in the clinical context of cardiomyopathies. Current guidelines recommend using LV ejection fraction as the only imaging-derived parameter to identify patients who may benefit from ICD implantation in cardiomyopathies with reduced ejection fraction; however, a relevant proportion of high-risk population is left with unmet therapeutic goal. In case of dilated, hypertrophic, or arrhythmogenic cardiomyopathies, there is still a room for more sensitive and specific risk markers for identifying a cluster at higher risk of SCD. In this paper, we reviewed the evidence supporting the use of advanced echocardiography, CMR, and nuclear cardiology for SCD stratification in patients with the most common cardiomyopathies. The added value of these modalities may be explained on the basis of tissue characterization, especially scar detection, a central player in the pathogenesis of arrhythmias. Therefore, integration of these modalities to our everyday clinical practice may help in dealing with the gray zones where current guidelines are still ineffective for patient selection.

A 16-year-old boy with bronchial asthma and prinzmetal angina: case report.

INTRODUCTION: Prinzmetal's angina is a very rare disease in children and adolescents. Adults' studies suggest that vasospastic angina is more common in patients with bronchial asthma than in the general population. CASE PRESENTATION: A 16-year-old boy with a history of bronchial asthma was admitted to the hospital after successful resuscitation from asystole. On the day of admission, he had a severe left shoulder pain and developed cardiac arrest. He was complaining of left shoulder pain throughout the previous year. During his hospital stay, a second cardiac arrest took place with inferior ST elevation of the electrocardiography recorded after the second successful resuscitation. Diagnostic coronary angiography revealed multiple spasms throughout the coronary bed, which was completely resolved after intracoronary nitroglycerine administration. The patient was diagnosed Printzmetal's vasospasic angina, and the symptoms disappeared gradually with up-titration of a calcium channel blocker and a nitrate. DISCUSSION: Previous studies have suggested that the pathogenesis of Prinzmetal's vasospastic angina may be similar to that of bronchial asthma, as we see in the presentation of this young patient.