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.
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.
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.
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 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.
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).
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.
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.
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.
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)
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
Enterovirus 71 (EV71) is one of the viruses that cause hand, foot and mouth disease. Its viral capsid protein 1 (VP1), which contains many neutralization epitopes, is an ideal target for vaccine development. Recently, we reported the induction of a strong immune response in rabbits to a truncated VP1 fragment (Nt-VP1t) displayed on a recombinant Newcastle disease virus (NDV) capsid protein. Protective efficacy of this vaccine, however, can only be tested in mice, since all EV71 animal models thus far were developed in mouse systems. In this study, we evaluated the type of immune responses against the protein developed by adult BALB/c mice. Nt-VP1t protein induced high levels of VP1 IgG antibody production in mice. Purified VP1 antigen stimulated activation, proliferation and differentiation of splenocytes harvested from these mice. They also produced significant levels of IFN-γ, a Th1-related cytokine. Taken together, Nt-VP1t protein is a potent immunogen in adult mice and our findings provide the data needed for testing of its protective efficacy in mouse models of EV71 infections.
Nucleotide sequence comparison of the L gene of the Malaysian neurotropic-viscerotropic velogenic NDV strain AF2240 with other NDV strains revealed a single nucleotide insertion at position 3870. This mutation is compensated by a nucleotide deletion downstream at position 3958 which results in two forms of the L proteins containing a 30-amino acid substitution in Domain V. This compensatory mutation does not correlate with the pathogenicity of the viral strains but it may affect the viral replication as Domain V is believed to play an important role in the replication of paramyxoviruses.
A random peptide library of heptamers displayed on the surface of M13 bacteriophage was used to identify specific epitopes of antibodies in pooled sera of swine naturally infected by Nipah virus. The selected heptapeptides were aligned with protein sequences of Nipah virus and several putative epitopes were identified within the nucleocapsid protein. A total of 41 of 60 (68%) selected phage clones had inserts resembling a region with the sequence SNRTQGE, located at the C-terminal end (amino acids 503-509) of the nucleocapsid protein. The binding of antibodies in the swine and human antisera to the phage clone was inhibited by a synthetic peptide corresponding to this region. Epitopes identified by phage display are consistent with the predicted antigenic sites for the Nipah virus nucleocapsid protein. The selected phage clone used as a coating antigen discriminated swine and human Nipah virus sera-positive from sera-negative samples exhibiting characteristics, which might be attractive for diagnostic tests.
A new organic-inorganic nanohybrid based on zinc-layered hydroxide intercalated with an anti-inflammatory agent was synthesized through direct reaction of salicylic acid at various concentrations with commercially available zinc oxide. The basal spacing of the pure phase nanohybrid was 15.73 Å, with the salicylate anions arranged in a monolayer form and an angle of 57 degrees between the zinc-layered hydroxide interlayers. Fourier transform infrared study further confirmed intercalation of salicylate into the interlayers of zinc-layered hydroxide. The loading of salicylate in the nanohybrid was estimated to be around 29.66%, and the nanohybrid exhibited the properties of a mesoporous-type material, with greatly enhanced thermal stability of the salicylate compared with its free counterpart. In vitro cytotoxicity assay revealed that free salicylic acid, pure zinc oxide, and the nanohybrid have a mild effect on viability of African green monkey kidney (Vero-3) cells.
Human respiratory syncytial virus is the most common cause of bronchiolitis and other respiratory infections in infants and the elderly worldwide. We have developed two new oral vaccines using Salmonella typhi TY21a to carry and express the immunogenic epitopes of RSV fusion (F) and attachment (G) glycoproteins on its surface, separately. To evaluate the efficacy of the designed vaccines, BALB/c mice were orally immunized and then infected with RSV. Immune response analyses showed that cellmediated, mucosal and humoral immunity in the vaccinated mice were significantly enhanced compared to the control group. Both vaccines generated a balanced Th1/Th2 immune response which is crucial for efficiency of vaccines against RSV. Furthermore, histopathological examination proved that these vaccines were safe as they did not cause any Th2-associated adverse effects in the lungs of RSV-infected mice. The findings of this research suggest that Salmonella-F and Salmonella-G vaccine candidates may have strong potential to prevent RSV infection.