Coronary angiography in heart failure: when and why? Uncertainty reigns

No abstract available

A keen eye for risk

No abstract available

Diabetes in Malta : current findings and future trends

Diabetes is a considerable global problem. Recent projections suggest that at least 194 million people suffer from diabetes worldwide. The World Health Organization suggests this number will increase to 333 million by 2025. Approximately four million deaths each year are caused by diabetes-related complications totaling an astounding 9% of deaths worldwide. Currently, epidemiological studies indicate that 1% of the Maltese population suffer from Type I Diabetes Mellitus and 9% from Type II Diabetes Mellitus. Following global predictions, it is probable that the incidence of Type I diabetes will increase also. This article evaluates the current Maltese diabetic care system and conducts a strategic analysis of diabetic practices. Recommendations for a cost-effective standard of care, legislative support for comprehensive diabetic care, and a national policy are proposed.peer-reviewe

Maternal awareness of health promotion, parental and preschool childhood obesity

Aim: To investigate the association between parental and preschool childhood obesity, as well as maternal awareness of public health promotion on healthy eating with parental and preschool childhood obesity. Methods: Data were collected by measuring the height and weight of two hundred randomly selected three-year old children and their parents. Details of the early feeding and dietary styles and level of health promotion awareness were assessed in faceto-face structured health interviews with the parents. Results: There were statistically significant relationships between childhood obesity and parents’ obesity (r=0.2; p<0.001). A higher proportion of overweight and obese preschool children showed that their mothers lacked awareness of health promotion as compared to children with normally accepted weight (χ2 (6, n=200)=17.32, p=0.008). Maternal awareness of health promotion on healthy eating appeared to have a protective effect against overweight/obesity in three year old children (odds ratio=0.38, 95% CI=0.20 to 0.70). Furthermore, a higher proportion of overweight/obesity mothers had no awareness of health promotion as compared to mothers with normally accepted weight (χ 2 (4, n=200)=13.29, p=0.01). Maternal awareness of health promotion appeared to also have a protective effect against overweight/obesity in mothers (odds ratio=0.51, 95% CI=0.28 to 0.95). Conclusions: This study showed the protective effect of maternal awareness of health promotion on maternal and preschool childhood obesity. Additionally, this study showed that overweight and obese preschool children had parents who were also overweight and obese.peer-reviewe

La enogastronomía del Perú, segunda propuesta culinaria

Los sentidos más importantes para degustar la comida y el vino son ciertamente el olfato y el gusto, dado que entregan informaciones directas sobre los alimentos y los vinos, pero no se debe absolutamente desestimar el efecto psicológico de la vista de una preparación alimentaria, porque tiene una influencia bastante grande

Progettazione e collaudo di un sistema di elaborazione ed acquisizione dati da un interferometro ottico.

In questo lavoro di tesi viene progettato, realizzato e collaudato un sistema di acquisizione ed elaborazione dei dati provenienti da un interferometro (Mach-Zehnder). Questo sistema di misura è stato realizzato in collaborazione con il Dipartimento di Ingegneria Chimica, Chimica Industriale e Scienza dei Materiali e ha lo scopo di caratterizzare la cinetica del meccanismo di reticolazione degli idrogeli di alginato. L'interesse per questo tipo di sostanze è notevole soprattutto in campo biomedico e va dal rilascio controllato di farmaci all' ingegneria tissutale vista l'elevata biocompatibilità. Il sistema è costituito dal trasduttore, una scheda di acquisizione dati (DAQ) ed un programma di elaborazione, visualizzazione ed archiviazione dei dati, realizzato con LabVIEW. La struttura scelta per il DAQ permette la comunicazione con un PC attraverso il bus USB, ed è tale da eseguire in futuro il controllo, attraverso degli I/O digitali, di un microposizionatore in modo da poter effettuare la caratterizzazione in posizioni diverse all'interno del materiale. Il software di elaborazione permette di visualizzare il segnale di calibrazione dell'interferometro e quello del fotorivelatore. Durante la misura elabora i dati e grafica le variazioni dell'indice di rifrazione nel tempo, in modo da caratterizzare così il meccanismo di reticolazione dell'idrogelo di alginato. I punti del grafico possono essere salvati su un file di testo

The potentiality of herbal remedies in Primary Sclerosing Cholangitis: from in vitro to clinical studies

Primary sclerosing cholangitis is a complex pathological condition, characterized by chronic inflammation and fibrosis of the biliary epithelium. Without proper clinical management, progressive bile ducts and liver damage lead to cirrhosis and, ultimately, to liver failure. The known limited role of current drugs for treating this cholangiopathy has driven researchers to assess alternative therapeutic options. Some herbal remedies and their phytochemicals have shown anti-fibrotic properties in different experimental models of hepatic diseases and, occasionally, in clinical trials in primary sclerosing cholangitis patients; however their mechanism of action is not completely understood. This review briefly examines relevant studies focusing on the potential anti-fibrotic properties of Silybum marianum, Curcuma longa, Salvia miltiorrhiza, and quercetin. Each natural product is individually reviewed and the possible mechanisms of action discussed

Hydralazine in heart failure: a study of the mechanism of action in human blood vessels

Hydralazine is a vasodilator that has been in clinical use for nearly six decades. Despite this, the mechanism of its action in human blood vessels is uncertain. Understanding how hydralazine works may have importance for the better treatment of heart failure and other cardiovascular diseases. In the first Vasodilator Heart Failure trial, hydralazine was shown, in combination with oral nitrates, to reduce mortality in patients with heart failure, treated at a time when the benefits of ACE inhibitors, beta-blockers and mineralocorticoid receptor antagonists were not known. As the combination of hydralazine and isosorbide dinitrate was subsequently shown to be less effective than an ACE inhibitor in the second Vasodilator Heart Failure trial, it was little used. Recently, however, the same combination was shown to reduce mortality and morbidity in the African-American Heart Failure Trial. Crucially, in this trial, the patients were already treated with the best currently available drug therapy. Though the patients studied were self-designated African-Americans, it is widely believed that the incremental benefits of the combination of hydralazine and isosorbide dinitrate are as likely to be obtained in other patients. While the vasodilator action of nitrates is well understood, a better understanding of the action of hydralazine (and its interaction with nitrates) could lead to the development of more effective and/or better-tolerated drugs. Nitrate therapy is limited by the development of pharmacological tolerance, possibly secondary to the increased production of reactive oxygen species. Hydralazine co-treatment has been shown to prolong the vasodilator effect of nitrates in animal models and clinical studies, although the mechanism of this protection in humans is uncertain. There are many postulated mechanisms of the vasodilator action of hydralazine, based upon studies carried out - mostly in animals - or animal tissues. Hydralazine reduces contractile responses to a number of vasoconstrictors, and this effect appears greater in arteries than in veins. The most (though not entirely) consistent findings are those suggesting that hydralazine leads to the activation of guanylate cyclase. This action to increase intracellular cGMP, could explain the favourable clinical benefits of its combination with oral nitrates. Hydralazine may affect a number of other vascular enzymes. These include key regulators of vascular superoxide production such as NAD(P)H oxidases. These systems are regulated in vivo and ex vivo by angiotensin-II and aldosterone, and are believed to be pivotal in the development of endothelial dysfunction, a key pathophysiological abnormality in heart failure. Renin-angiotensin system activation and oxidative stress are important (and inter-related) pathophysiological processes in heart failure and other cardiovascular problems. There is experimental evidence that hydralazine may inhibit these vascular and mitochondrial oxidases, and may also act as a radical scavenger, thus helping restore the balance between NO and superoxide in endothelial dysfunction. Inhibition of superoxide production may also help prevent nitrate tolerance: this may be critical in permitting therapeutic synergy between hydralazine and nitrates. However, the evidence emanating from different animal species is contradictory. Surprisingly, the antioxidant effect of hydralazine has never been directly characterised in human blood vessels. In this thesis I investigated the action of hydralazine in human blood vessels. To make this project clinically relevant, I characterised the actions of hydralazine in arteries and veins of various calibre (saphenous vein and internal mammary artery taken at the time of coronary artery bypass surgery and subcutaneous resistance arteries dissected from gluteal biopsies), from patients with low ejection fraction heart failure secondary to coronary artery disease. I also investigated the purported ability of hydralazine to reduce vascular superoxide production. 40 patients undergoing elective coronary artery bypass surgery were recruited for large vessel studies and 20 patients underwent gluteal biopsy, which yielded subcutaneous resistance arteries. Vascular reactivity was assessed using organ bath techniques and wire myography with the construction of cumulative concentration response curves. Production of vascular superoxide was measured using lucigenin chemiluminescence. Summary of results: 1. There was no direct vasodilator effect of hydralazine at therapeutic concentrations (<1 µmol/L). This suggests that the favourable benefits of hydralazine are not simply dependent on direct vasodilatation. 2. There was a modest – but not statistically significant – interaction between hydralazine and endothelium-dependent vasodilatation using carbachol. This is consistent with a trend of potential biological relevance. There was a similarly modest interaction with organic nitrates. These data are consistent with theories that the therapeutic benefits of hydralazine may be partly explained by improved endothelium-dependent vasodilatation and that the interaction with organic nitrates in vivo is not simply dependent on augmented vasodilatation. 3. Hydralazine reduced basal superoxide production in both internal mammary artery [1.09 ± 0.14 nmol/mg/min vs. 0.77 ± 0.16 nmol/mg/min (P=0.026) controls and pre-treated vessels respectively] and saphenous veins [0.77 ± 0.08 nmol/mg/min vs. 0.68 ± 0.08 nmol/mg/min (P=0.018) controls and pre-treated vessels respectively]. A dose-response in superoxide production in saphenous vein (which were more readily available for experimentation) was also evident. 4. Hydralazine significantly inhibited angiotensin-II mediated superoxide production in internal mammary arteries [1.68 ± 0.434 nmol/mg/min vs. 0.843 ± 0.144 nmol/mg/min (P=0.032) controls and pre-treated vessels respectively]. Angiotensin II plays a key role in the pathophysiology of heart failure, with pleotropic effects including increased vascular superoxide production through stimulation of NAD(P)H oxidase. Attenuation of angiotensin-II stimulated superoxide production by hydralazine could mechanistically be through interaction with the NAD(P)H oxidase enzyme group; supporting the best available animal data suggesting that hydralazine prevents nitrate tolerance through modulation of this enzyme group. Appropriate recognition must be had to the limitations innate in this work and recognise that all protocols were ex vivo and, as such, none could accurately reflect the complex phenotype recognised in chronic heart failure. The relatively small sample sizes in the study protocols must also be given recognition; however, my group - and others - have published, scientifically meaningful results utilising similar sample sizes. Future developments ought to include larger scale bench and in vivo studies of hydralazine and organic nitrate interaction with particular emphasis on assessing endothelium-dependent vasodilatation. In my studies hydralazine functionally reduced vascular superoxide production; future studies will evaluate this mechanistically with particular emphasis on the NAD(P)H oxidase system

Post-operative myocardial infarction following aortic root surgery with coronary reimplantation: a case series treated with percutaneous coronary intervention

Background: Coronary ostial stenosis is an uncommon but potentially lethal complication following aortic root replacement with or without aortic valve replacement (including Bentall and David procedures). This manifests clinically as acute myocardial ischaemia in the early or late post-operative period. Traditionally, this might be managed with redo open-heart surgery. Case summary:  This case series describes two presentations where urgent percutaneous coronary intervention was used to manage myocardial infarction complicating aortic root surgery with coronary reimplantation. Discussion: This series highlights the risk of acute myocardial infarction after cardiac surgery involving coronary reimplantation. Emergency percutaneous coronary intervention is feasible and illustrates the importance of shared post-operative care involving the cardiac surgeons and the cardiology team

Reactivity of Heteropolytungstate and Heteropolymolybdate Metal Transition Salts in the Synthesis of Dimethyl Carbonate from Methanol and CO2

A series of Keggin-type heteropoly compounds (HPC) having different countercations (Co, Fe) and different addenda atoms (W, Mo) were synthesized and characterized by means of Fourier-Transform Infrared Spectrometer (FT-IR) and X-ray powder diffraction (XRD). The catalytic properties of the prepared catalysts for the dimethyl carbonate (DMC) synthesis from CO2 and CH3OH were investigated. The experimental results showed that the catalytic activity is significantly influenced by the type of the countercation and addenda atoms transition metal. Among the catalysts examined, Co1.5PW12O40 is the most active for the DMC synthesis, owing to the synergetic effect between Co and W. Investigating the effect of the support showed that the least acidic one (Al2O3) enhanced the conversion but decreased the DMC selectivity in favor of that of methyl formate (MF), while that of dimethoxy methane remained stable