Cost-effective intervention in stroke

Antihypertensive Activities of a Solid-State Culture ofTaiwanofungus camphoratus(Chang-Chih) in Spontaneously Hypertensive Rats

Wild and solid-state cultures (SSC) of Taiwanofungus camphoratus (aka Antrodia camphorata and Chang-chih [CC]) were sequentially extracted with cold water, methanol, and hot water to get cold-water-soluble (CWS), methanol-soluble (MS), and hot-water-soluble (HWS) extracts, respectively. Only the MS extract exhibited angiotensin-converting enzyme (ACE) inhibitory activities. The antihypertensive effects of the MS extract (10 mg/kg BW) were measured in spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats. MS extract of the SSC type was able to effectively lower the systolic blood pressure (SBP) and diastolic blood pressure (DBP) of SHR, but not of WKY rats, the results being significantly different from those for distilled water only (the blank). However, wild CC and its MS extract were not as effective as the SSC type in reducing SHR blood pressure and had no effect on WKY rats. SSC-type CC might be developed into a health food with the ability to regulate blood pressure.

Formal-Transfer In and Out of Stroke Care Units

The positive impact of stroke care units (SCUs) on patient outcome has been previously reported. In this study, long-term stroke patients that are formally admitted to teaching-hospitals are compared with and without SCUs. The authors focus on the patients’ experience with ongoing care or formal transfers following current care as this cohort is often high users of the system with associated high costs. Bayesian Networks were employed to analyze routinely collected public-hospital administrative data. The results illustrate that the teaching-hospitals with SCUs, while achieving shorter length of stay, in fact deal with younger patients with lower overall patient complexity than non-SCU teaching-hospitals. Other differences include SCUs predominantly treating subarachnoid hemorrhages whereas the non-SCUs treat more cerebral infarctions. This study illustrates the power of Bayesian Networks to expose the nature of caseload and outcomes recorded in hospital-administrative data as a means to gain insight on current practice and create opportunities for benchmarking and improving care.

Stroke and cardiovascular diseases: the need for a global approach for prevention and drug development

BACKGROUND

Research into the prevention and treatment of stroke and cardiovascular disease has focused primarily on the needs of high-income countries (HIC). However, the majority of all stroke and cardiovascular deaths occurs in low- and middle-income countries (LMIC), with further rises in these countries predicted.

SUMMARY OF REVIEW

In HIC, proven strategies for the treatment of stroke and cardiovascular disease are well established and cost-effective. Developing strategies to include LMIC is therefore crucial to curb the global epidemic of stroke and cardiovascular disease. For example, pharmaceutical companies are being encouraged to make certain drugs more affordable in low- and middle-income companies, and the same principle could be applied to drugs for the prevention of stroke. Furthermore, centers from LMIC are now often included in clinical trials, resulting in trials that are more globally relevant and affordable and that enhance the participation of healthcare professionals from a broad range of countries.

CONCLUSIONS

More cost-effective drug development processes and affordable prices, while protecting intellectual property rights, will prevent the ever-increasing burden of stroke becoming unmanageable in LMIC.

Recorded Categories of Non-Principal Diagnoses in Victorian Public Hospital Transient Ischaemic Attack and Stroke Admissions

Information about the number and types of non-principal diagnoses (NPDs) would make an important contribution to prediction of outcome and hence patient management. The study reported here is based on analysis of three fiscal years of the Victorian public hospital transient ischaemic attack (TIA) and stroke admissions. The incidence of NPDs and co-occurrence of NPD-associated prefix categories (that identify the onset or relevance of each condition to the episode) are described in each of the broad stroke subtypes. The distributions of length of stay and in-hospital deaths in the cohorts without and with NPDs and in the various prefix categories are determined. The study also compares the age and gender distribution in the various subpopulations of interest. The importance of collecting complete and accurate data on nature of NPDs and its potential in describing the complexity of presentation are discussed.

Synthesis and evaluation of methyl 2-methoxycarbonyl-3-phenylpropionate derivatives as a new type of angiotensin converting enzyme inhibitors

Methyl 2-methoxycarbonyl-3-phenylpropionate derivatives were prepared, and their inhibitory activities for angiotensin converting enzyme (ACE) were evaluated. Compounds 5b (IC50 = 0.0039 µmol/L), 5d (IC50 = 0.0027 µmol/L), 5e (IC50 = 0.0021 µmol/L), and5f (IC50 = 0.0052 µmol/L) exhibited more potent ACE inhibitiory activity than the control drug Captopril® (IC50 = 0.0075 µmol/L).Key words: hypertension, 2-methoxycarbonyl-3-phenyl propionate derivative, ACE inhibitor.

Feasibility of Stent Placement in Carotid Arteries with Real-time MR Imaging Guidance in Pigs

All examinations were performed with approval from the institutional animal care and use committee of Columbia University. To assess the feasibility of real-time magnetic resonance (MR) imaging-guided neurovascular intervention in a swine model, the authors placed stents in the carotid arteries of five domestic pigs. Seven-French vascular sheaths were placed in the target carotid arteries via femoral access by using active MR tracking. Ten nitinol stents (8-10 x 20-40 mm) were successfully deployed in the target segments of carotid arteries bilaterally. MR imaging and necropsy findings confirmed stent position. Necropsy revealed no gross vascular injury. Study results demonstrated the feasibility of performing real-time MR imaging-guided neurovascular intervention by using an active-tracking technique in an animal model.

Trial Application of a Model of Resource Utilization, Costs, and Outcomes for Stroke (MORUCOS) to Assist Priority Setting in Stroke

Background and Purpose— Cost-effectiveness data for stroke interventions are limited, and comparisons between studies are confounded by methodological inconsistencies. The aim of this study was to trial the use of the intervention module of the economic model, a Model of Resource Utilization, Costs, and Outcomes for Stroke (MORUCOS) to facilitate evaluation and ranking of the options.

Methods— The approach involves using an economic model together with added secondary considerations. A consistent approach was taken using standard economic evaluation methods. Data from the North East Melbourne Stroke Incidence Study (NEMESIS) were used to model “current practice” (base case), against which 2 interventions were compared. A 2-stage process was used to measure benefit: health gains (expressed in disability-adjusted life years [DALYs]) and filter analysis. Incremental cost-effectiveness ratios (ICERs) were calculated, and probabilistic uncertainty analysis was undertaken.

Results— Aspirin, a low-cost intervention applicable to a large number of stroke patients (9153 first-ever cases), resulted in modest health benefits (946 DALYs saved) and a mean ICER (based on incidence costs) of US $1421 per DALY saved. Although the health gains from recombinant tissue-type plasminogen activator (rtPA) were less (155 DALYs saved), these results were impressive given the small number of persons (256) eligible for treatment. rtPA dominates current practice because it is more effective and cost-saving.

Conclusions— If used to assess interventions across the stroke care continuum, MORUCOS offers enormous capacity to support decision-making in the prioritising of stroke services.

Inhibitory activities of semicarbazide-sensitive amine oxidase and angiotensin converting enzyme of pectin hydroxamic acid

Solutions of 100 mL of 1% commercial pectin each with a different degree of esterification (DE), DE94, DE65, and DE25, were reacted with 100 mL of 2 M alkaline hydroxylamine (pH 12.0) at room temperature for 4 or 18 h. These pectin hydroxamic acids (PHAs; DE94T4, DE94T18, DE65T4, and DE25T4) were used to test the inhibitory activities against semicarbazide-sensitive amine oxidase (SSAO) and angiotensin-converting enzyme (ACE). Compared to different DE pectins (DE94, DE65, and DE25), the PHAs of DE94T4, DE94T18, DE65T4, and DE25T4 showed different inhibition activities against SSAO or ACE. Commercial pectins with different DE values showed negligible SSAO or ACE inhibitions. The order of SSAO inhibition was DE65T4 > DE94T18 approximately DE25T4 >> DE94T4. However, the order of ACE inhibition was DE94T4 > DE94T18 >> DE65T4 > DE25T4. The SSAO activity staining or ACE-hydrolyzed products on TLC chromatogram also confirmed the inhibitory activities of PHAs against SSAO or ACE.

A benefit-risk assessment of agents used in the secondary prevention of stroke

Stroke is a major cause of morbidity and mortality. Full assessment of stroke or transient ischaemic attack (TIA) patients is required to identify all risk factors and apply appropriate secondary preventative strategies. Antiplatelet therapies are effective in the secondary prevention of ischaemic stroke and can be justified despite adverse effects such as gastrointestinal haemorrhage. Aspirin (acetylsalicylic acid), aspirin plus dipyridamole, ticlopidine and clopidogrel are all of value but their adverse effect profiles vary significantly. Combinations of antiplatelet agents may offer additional benefit but not all combinations have been studied in stroke patients. Anticoagulation with agents such as warfarin is effective with coexisting atrial fibrillation and other conditions predisposing to cardioembolic stroke. Antihypertensive agents have been extensively studied in the primary prevention of stroke; however, relatively few trials of antihypertensive agents in the secondary prevention of stroke are available. The incidence of adverse effects of antihypertensive agents is relatively low and the benefit-risk profile would tend to favour their use in the secondary prevention of stroke. Recent studies of ACE inhibitors have identified an important role for these agents in the secondary prevention of stroke even in those who are normotensive and in those who have had a haemorrhagic stroke. The incidence of serious adverse effects with ACE inhibitors appears relatively low. Lipid-lowering agents may have a role to play in certain groups of patients with stroke. The incidence of adverse effects is relatively low with HMG-CoA reductase inhibitors. Cigarette smoking is an important risk factor for stroke and evidence is available that smoking cessation does reduce the individual's risk of stroke. Pharmacological agents are available to help smoking cessation. In patients with diabetes mellitus, intensive regimens with insulin and oral hypoglycaemic agents have so far not definitively been shown to reduce the incidence of macrovascular complications such as stroke. Tight glycaemic control has been shown to improve microvascular complications such as retinopathy, nephropathy and neuropathy and hence this is reason enough to advocate the use of these agents. Future developments in the treatment of diabetes may help. Secondary prevention of stroke has improved greatly over the past decade and hopefully will continue to improve. The use of pharmacological agents available currently and in the future will be clarified and refined as further clinical trials report.

Antioxidant peptides with Angiotensin converting enzyme inhibitory activities and applications for Angiotensin converting enzyme purification

Five commercial peptides, namely, reduced glutathione (GSH), oxidized glutathione (GSSG), carnosine, homocarnosine, and anserine, were used to test angiotensin converting enzyme inhibitory (ACEI) activities using N-[3-(2-furyl)acryloyl]-Phe-Gly-Gly (FAPGG) as a substrate. All of these peptides showed dose-dependent ACEI activities. Using 50% inhibition (IC(50)) of captopril as 0.00781 microM for the reference, the IC(50) values of GSH, carnosine, homocarnosine, and anserine were determined to be 32.4 microM, 5.216 mM, 6.147 mM, and 6.967 mM, respectively. GSH or carnosine showed mixed noncompetitive inhibition against ACE. When 0.0164 mM GSH or 0.4098 mM carnosine was added, the apparent inhibition constant (K(i)) was 49.7 microM or 3.899 mM, respectively. Commercial glutathione-Sepharose 4 fast flow, GSH-coupled CNBr-activated and GSH-coupled EAH-activated Sepharose gels were used for ACE purification. Commercial ACE could be adsorbed only by EAH-coupled GSH gels and eluted off the gels by increasing salt concentrations. These EAH-coupled GSH gels might be developed as affinity aids for ACE purification.

The rising cost of health care: can demand be reduced through more effective health promotion?

The cost of health care continues to rise in the face of an apparently insatiable demand. Unless the actual need for health care can be reduced to manageable levels, the financial burden will probably become economically unacceptable. Although some illnesses are unavoidable, others that are largely due to unhealthy lifestyles are preventable. Circulatory diseases, diabetes and some cancers, which are major causes of morbidity and mortality in western societies, are strongly linked to physical inactivity, psychological stress, unhealthy eating, obesity and smoking. There is ample evidence that promotion of healthy lifestyles, including physical activity, healthy eating and non-smoking, are effective for the primary and secondary prevention of these diseases. Although there are examples of successful public health programmes that have encouraged more healthy lifestyles and reduced the burden of disease, we need to be much more effective in putting theory into practice. In order to improve the health of the nation and to prevent the economy being overwhelmed by the increasing demand for health care, we need a change of mindset from a consumerist approach to an acceptance of personal and corporate responsibility for more healthy lifestyles. Widespread collaboration among health care agencies, private and public utilities, the entertainment industry and the communications media will be necessary in order to provide the necessary incentives for lifestyle changes.

Both dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), and its peptic hydrolysates exhibited angiotensin converting enzyme inhibitory activities

Dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), was purified to homogeneity by DE-52 ion-exchange chromatography. This purified dioscorin was shown by spectrophotometric methods to inhibit angiotensin converting enzyme (ACE) in a dose-dependent manner (12.5-750 microg, respectively, 20.83-62.5% inhibitions) using N-[3-(2-furyl)acryloyl]-Phe-Gly-Gly (FAPGG) as substrates. The 50% inhibition (IC(50)) of ACE activity was 6.404 microM dioscorin (250 microg corresponding to 7.81 nmol) compared to that of 0.00781 microM (0.0095 nmol) for captopril. The commercial bovine serum albumin and casein (bovine milk) showed less ACE inhibitory activity. The use of qualitative TLC also showed dioscorin as ACE inhibitors. Dioscorin showed mixed noncompetitive inhibitions against ACE; when 31.25 microg of dioscorin (0.8 microM) was added, the apparent inhibition constant (K(i)) was 2.738 microM. Pepsin was used for dioscorin hydrolysis at 37 degrees C for different times. It was found that the ACE inhibitory activity was increased from 51.32% to about 75% during 32 h hydrolysis. The smaller peptides were increased with increasing pepsin hydrolytic times. Dioscorin and its hydrolysates might be a potential for hypertension control when people consume yam tuber.

Cerebral microvascular changes in permeability and tight junctions induced by hypoxia-reoxygenation

Cerebral microvessel endothelial cells that form the blood-brain barrier (BBB) have tight junctions (TJ) that are critical for maintaining brain homeostasis and low permeability. Both integral (claudin-1 and occludin) and membrane-associated zonula occluden-1 and -2 (ZO-1 and ZO-2) proteins combine to form these TJ complexes that are anchored to the cytoskeletal architecture (actin). Disruptions of the BBB have been attributed to hypoxic conditions that occur with ischemic stroke, pathologies of decreased perfusion, and high-altitude exposure. The effects of hypoxia and posthypoxic reoxygenation in cerebral microvasculature and corresponding cellular mechanisms involved in disrupting the BBB remain unclear. This study examined hypoxia and posthypoxic reoxygenation effects on paracellular permeability and changes in actin and TJ proteins using primary bovine brain microvessel endothelial cells (BBMEC). Hypoxia induced a 2.6-fold increase in [(14)C]sucrose, a marker of paracellular permeability. This effect was significantly reduced (~58%) with posthypoxic reoxygenation. After hypoxia and posthypoxic reoxygenation, actin expression was increased (1.4- and 2.3-fold, respectively). Whereas little change was observed in TJ protein expression immediately after hypoxia, a twofold increase in expression was seen with posthypoxic reoxygenation. Furthermore, immunofluorescence studies showed alterations in occludin, ZO-1, and ZO-2 protein localization during hypoxia and posthypoxic reoxygenation that correlate with the observed changes in BBMEC permeability. The results of this study show hypoxia-induced changes in paracellular permeability may be due to perturbation of TJ complexes and that posthypoxic reoxygenation reverses these effects.

Stroke: development, prevention and treatment with peptidase inhibitors

Stroke is the leading cause of long-term disability in the United States and affects more people than any other neurologic disorder. Hypertension is a major risk factor associated with stroke. Several anti-hypertensive agents have been used to treat chronic hypertension to reduce the morbidity and mortality of stroke. Previous experimental studies have shown reduced stroke mortality with angiotensin-converting enzyme (ACE) inhibitors. This review discusses the development of stroke and potential use of ACE inhibitors in prevention and treatment of this disease. Furthermore, this review focuses on current investigations aimed at cellular mechanisms involved in stroke-induced microvascular alterations.