New knowledge on the pathogenesis of the acute coronary syndromes provides the clinician with a better understanding of these important, often life-threatening, events and opens up new ways of managing them. The identification of the vulnerable plaque whilst important and possible pathologically still requires elaborate and often invasive methods. The central role of inflammation and the platelets in these syndromes has already been translated into practical therapeutics. Identifying and predicting which plaque would rupture and thereby facilitating the formation of an acute obstructive thrombus continue as major challenges to the clinician, but, in the meantime, regressing and stabilising these plaques are achievable goals.
Getting through major surgeries safely and timely with success and minimal complications is one of the great achievements of modern medicine. As the surgical techniques and the organs and systems involved become more varied, there are a number of important issues which determine the success of surgery. But one overriding theme is cardiovascular stability during and immediately after surgery.
ALLHAT study is the biggest randomized clinical trial in hypertension ever conducted. Its objective was to ompare the efficacy of newer (calcium channel blocker amlodipine and angiotensin-converting enzyme inhibitor inopril) to the older (diuretic chlorthalidone) antihypertensive agents in the treatment of patients with hypertension. After enrolling 42,000 patients who were followed for an average of 4.9 years, ALLHAT did not find significant differences in the primary end-points between these antihypertenive agents. ALLHAT however found significant differences in the secondary end-points such as heart failure and strokes between chlorthalidone and amlodipine or lisinopril. Based on these and on economic reasons, the investigators unequivocally recommended diuretics as the first line therapy for hypertension. Since its publication, ALLHAT has been much discussed, debated A and opined. The choice of drugs for study, the study design, the conduct of the study and the conclusions drawn by the investigators had all been criticised or controversial. Yet ALLHAT has been widely quoted, commented upon or referred to and it has been instrumental in initiating the JNC VII Guidelines. Thus a thorough understanding of ALLHAT is necessary for clinical practice and in designing and evaluating clinical trials in the future. Moving Points: in Medicine will capture the essence of ALLHAT, discusses its implications to clinical trials and explores its possible impact on the practice of medicine in this country.
Cardiovascular disease, in particular coronary artery disease (CAD), remains the most important cause of morbidity and mortality in developed countries and, in the near future, more so in the developing world. Atherosclerotic plaque formation is the underlying basis for CAD. Growth of the plaque leads to coronary stenosis, causing a progressive decrease in blood flow that results in angina pectoris. Acute myocardial infarction and unstable angina were recently recognised as related to plaque rupture, not progressive coronary stenosis. Acute thrombus formation causes an abrupt coronary occlusion. The characteristics of the fibrin cap, contents of the plaque, rheological factors and active inflammation within the plaque contribute to plaque rupture. Oxidative processes are important in plaque formation. Oxidized low density lipoproteins (LDL) but not unoxidized LDL is engulfed by resident intimal macrophages, transforming them into foam cells which develop into fatty streaks, the precursors of the atherosclerotic plaque. Inflammation is important both in plaque formation and rupture. Animal studies have shown that antioxidants reduce plaque formation and lead to plaque stabilisation. In humans, high intakes of antioxidants are associated with lower incidence of CAD, despite high serum cholesterol levels. This observation suggests a role for inflammation in CAD and that reducing inflammation using antioxidants may ameliorate these processes. Men and women with high intakes of vitamin E were found to have less CAD. Vitamin E supplementation was associated with a significant reduction in myocardial infarction and cardiovascular events in the incidence of recurrent myocardial infarction. In the hierarchy of evidence in evidence-based medicine, data from large placebo-controlled clinical trials is considered necessary. Results from various mega-trials have not shown benefits (nor adverse effects) conferred by vitamin E supplementation, suggesting that vitamin E has no role in the treatment of CAD. These results do not seem to confirm, at the clinical level, the effect of antioxidants against active inflammation during plaque rupture. However, a closer examination of these studies showed a number of limitations, rendering them inconclusive in addressing the role of vitamin E in CAD prevention and treatment. Further studies that specifically address the issue of vitamin E in the pathogenesis of atherosclerosis and in the treatment of CAD need be performed. These studies should use the more potent antioxidant property of alpha-tocotrienol vitamin E.
Vitamin E is known to have potent antioxidant activity and plays an important role in reducing oxidative stress, a pivotal step in atherogenesis. However, several randomised clinical trials using α-tocopherol have failed to demonstrate consistent beneficial effects of antioxidants against atherosclerosis and clinical endpoints. Tocotrienol, a vitamin E compound analogue is shown to have more potent antioxidant activity compared to tocopherol. Finding the optimal anti-oxidative dose is crucial and may effectively be applied for cardioprotection in human. The objective of this study was to determine the optimal dose of tocotrienol rich fraction (TRF) with highest antioxidant activity in vitro using the ferric thiocyanate (FTC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and 2’, 7’- dichlorofluorescein diacetate (DCFHDA) assays. It was found that TRF exhibited potent antioxidant and free radical scavenging activities with an IC50 of 22.10 + 0.01 µg/ml. In all assays, TRF had optimal antioxidant activity at moderate concentrations (10-100 µg/ml). In conclusion, TRF has potent antioxidant activity, which is optimal at moderate concentrations.
Cardiac arrhythmias are common in patients with thyrotoxicosis. Conduction abnormalities have been seen in a few thyrotoxic patients, but these, in particular high grade atrioventricular (AV) block, often occur in the presence of other conditions. Three thyrotoxic patients with conduction abnormalities are described: two were associated with severe hypokalaemia and the third had congestive cardiac failure. Conditions predisposing to conduction abnormality should be identified when this occurs in a thyrotoxic patient as their correction may help resolve or explain the conduction abnormality.
A total of 209 randomly selected Malaysian university students (128 from Universiti Kebangsaan Malaysia, 81 from the University of New South Wales) completed a self-filled questionnaire enquiring about their smoking behaviour and psychosocial characteristics. The prevalence of smoking was 26.6 per cent among students in Malaysia and 18.8 per cent among students in Australia (average 23.4%). Both samples have similar patterns in terms of age of starting smoking, time of the day when they smoked, family and peer history of smoking, and whether or not they inhaled deeply during smoking. The smokers tend to be male, studying beyond the first year, staying with peers outside the hostel, having financial sources other than a scholarship, and abnormal mental health score. However, the smokers from the Australian samples were noted to smoke less and made fewer attempts at quitting the habit.
Recently it was shown that following infection of HeLa cells with Newcastle disease virus (NDV), the matrix (M) protein binds to Bax and subsequently the intrinsic pathway of apoptosis is activated. Moreover, there was very little alteration on mRNA and protein levels of Bax and Bcl-2 after infection with NDV.
The ultimate goal of human genetics is to understand the role of genome variation in elucidating human traits and diseases. Besides single nucleotide polymorphism (SNP), copy number variation (CNV), defined as gains or losses of a DNA segment larger than 1 kb, has recently emerged as an important tool in understanding heritable source of human genomic differences. It has been shown to contribute to genetic susceptibility of various common and complex diseases. Despite a handful of publications, its role in cardiovascular diseases remains largely unknown. Here, we deliberate on the currently available technologies for CNV detection. The possible utility and the potential roles of CNV in exploring the mechanisms of cardiac remodeling in hypertension will also be addressed. Finally, we discuss the challenges for investigations of CNV in cardiovascular diseases and its possible implications in diagnosis of hypertension-related left ventricular hypertrophy (LVH).
Influenza A virus is a particularly problematic virus because of its ability to cause high levels of morbidity on a global scale within a remarkably short period of time. It also has the potential to kill very large numbers of people as occurred in the Spanish influenza pandemic in 1918. Options for antiviral therapy are limited because of the paucity of available drugs and the rapid mutation rate of the virus leading to the emergence of drug-resistant strains. The current H1N1 pandemic and potential threats posed by other strains highlight the need to develop novel therapeutic and prophylactic strategies. Here, we summarize the current state and recent developments of peptide-based inhibitors of influenza A virus.
The yeast two-hybrid system has been used to identify domains of the Newcastle disease virus (NDV) phosphoprotein (P) involved in self-association and interaction with the nucleocapsid protein (NP). Deletion analysis was used to map the domain(s) of the P protein involved in P:P and P:NP interactions. The C-terminal 45 amino acids (residues 247-291) were shown to play a major role in both of the interactions. Comparison of these findings with other reports suggests that paramyxoviruses are different with respect to interaction domain(s) between these two essential viral proteins involved in genome replication.
BACKGROUND: The benefit of adding theophylline to beta 2 agonists in acute asthmatic attacks has been debated frequently.
METHODS: In an open randomised study 25 patients with severe acute asthma who presented to the emergency department were treated with either a combined nebulised salbutamol (5 mg/dose) and aminophylline infusion (0.6-0.9 mg/kg/hour), or nebulised salbutamol alone.
RESULTS: The responses to treatment as measured by peak expiratory flow (PEF) and the time taken to achieve maximum PEF were similar in both groups. Side effects were observed more commonly in patients receiving the combined treatment.
CONCLUSIONS: Nebulised salbutamol is equally efficacious in acute asthma when given alone or in combination with aminophylline.
Study site: Emergency department, Hospital Kuala Lumpur, Malaysia
One hundred consecutive patients attending the UKM (Universiti Kebangsaan Malaysia) Cardiology Clinic completed a questionnaire enquiring about their own assessment of their knowledge about their illness, their awareness of cardiac risk factors and their expectations in their management. Only 11% of our patients had graduated from tertiary education. 59% of our patients were being treated for ischaemic heart disease. Although only 28% of our patients considered having considerable knowledge of their illness, a majority of our patients were aware of cardiac risk factors. This was independent of the formal education achieved. However this awareness did not necessarily result in appropriate behaviour; 32% of patients admitted to smoking despite being aware of the harmful effects of smoking. 74% of our patients expected a cure from their doctors; only 37% of our patients thought they required medication indefinitely. Thus, patients could be made aware of their illness regardless of their formal educational status. However this may not necessarily result in appropriate behaviour. The high expectations which the patients have of their doctors is unrealistic and may be detrimental to appropriate long-term management of their chronic illness.
Study site: Cardiology Clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM)
Prevalence of hypertension (HTN) varies substantially across different populations. HTN is not only common - affecting at least one third of the world's adult population - but is also the most important driver for cardiovascular diseases. Yet up to a third of hypertensive patients are resistant to therapy, contributed by secondary hypertension but more commonly the hitherto inability to precisely predict response to specific antihypertensive agents. Population and individual genomics information could be useful in guiding the selection and predicting the response to treatment - an approach known as precision medicine. However this cannot be achieved without the knowledge of genetic variations that influence blood pressure (BP). A number of evolutionary factors including population demographics and forces of natural selection may be involved. This article explores some ideas on how natural selection influences BP regulation in ethnically and geographically diverse populations that could lead to them being susceptible to HTN. We explore how such evolutionary factors could impact the implementation of precision medicine in HTN. Finally, in order to ensure the success of precision medicine in HTN, we call for more initiatives to understand the genetic architecture within and between diverse populations with ancestry from different parts of the world, and to precisely classify the intermediate phenotypes of HTN.
Nine Newcastle disease virus (NDV) isolates from Newcastle disease (ND) outbreaks in different regions of Iran were characterized at molecular level. Sequence analysis revealed that the isolates shared two pairs of arginine and a phenylalanine at the N-terminus of the fusion (F) protein cleavage site similarly to other velogenic isolates of NDV characterized earlier. Eight of the nine isolates had the same amino acid sequence as VOL95, a Russian NDV isolate from 1995. However, one isolate, MK13 showed 5 amino acid substitutions, of which 3 have been reported for other velogenic NDV isolates. These results suggest that the origin of the outbreaks of ND in different parts of Iran in 1995-1998 is VOL95.
Laboratories intending to adopt cycle sequencing of PCR products in their routine analysis often face a confusing range of methods and kits. Through the study of mitochondrial cytochrome b, we have shown that clean and highly reproducible sequences could be obtained by using a combination of existing simple and economical methods in the preparation of DNA templates, PCR, purification of PCR products and sequencing. Our protocol is useful in itself or as a standard in typing other PCR-amplified DNA at the population level.
A total of 143 microsatellites were isolated from Mystus nemurus using a 5' anchored polymerase chain reaction technique or the random amplified hybridization microsatellite method, the first set of microsatellite markers developed for the Southeast Asian river catfish. Twenty polymorphic microsatellite loci were used as markers for population characterization of M. nemurus from six different geographical locations in Malaysia (Perak, Kedah, Johor, UPM, Sarawak and Terengganu). The number of alleles per locus ranged from 2 to 11 with 6.3 as the average number of alleles per locus. Characterization of the populations showed relatively high levels of genetic variation compared with previous studies using allozyme markers. The highest genetic similarity was found between Perak and Kedah, while the highest genetic distance was found between Terengganu and Kedah. The majority of clustering was in accordance with geographical locations and the histories of the populations. Microsatellite analysis indicated that the Sarawak population might be genetically closer to the Peninsular Malaysian populations than has been previously shown by other molecular marker studies.
Destructive thyroiditis commonly occurs during the postpartum period, with a prevalence rate of 5% to 16%, and is mainly due to postpartum autoimmune thyroiditis (PPT) and, very rarely, to subacute thyroiditis. The thyroiditis is similar to Hashimoto's thyroiditis and is generally painless in nature, although cases with painful thyroiditis have been described. We report a case of painful destructive thyroiditis occurring during the postpartum period, which was clinically and biochemically indistinguishable from the variant of painful PPT or subacute thyroiditis. Fine needle aspiration cytology showed multi-nucleated giant cells diagnostic of subacute thyroiditis.