Smokeless tobacco use in Myanmar.

Smokeless tobacco (SLT) use in various forms is highly prevalent in Myanmar. The aim of this paper is to study the socio-cultural background of SLT use and products of SLT in Myanmar and the prevalence of SLT based on surveys and from other published data bases. Information was obtained from the literature review and through search on PubMed and Google. The use of SLT is deep rooted in Myanmar culture, and there is also wide-spread belief that it is not as dangerous as smoking. SLT use is growing in Myanmar. About 9.8% of the 13-15-year-old school children and 20.8% adults use SLT; it is many-fold higher among men. The use of SLT is prevalent using many different types of tobacco and forms of its use in Myanmar. The socio-cultural acceptance and the myths were compounded by the lack of specific SLT control component in the National Tobacco Control Legislation adopted needs to be addressed as a priority through intensified community awareness programs, public education programs, and advocacy campaigns. Effective enforcement of the law and amendment to include specific components of SLT in the provisions of the law is highly recommended. The prevalence of SLT is high among school children and adults (especially in men) in Myanmar. Betel quid and tobacco is a common form of SLT use. Although control of smoking and consumption of tobacco product law exists, its implementation is weak.

CD133+ endothelial progenitor cells as a potential cell source for a bioartificial glomerulus.

Development of a bioartificial glomerulus, a hemofilter in which the inner surface of hollow fibers is endothelialized, requires expandable, nonimmunogenic, antithrombogenic, and highly permeable endothelial cells. We used human umbilical cord blood CD133(+) endothelial progenitor cells (EPCs) to evaluate the feasibility of application of EPCs for bioartificial glomerulus. Numbers of adhered CD133(+) EPCs (adhered EPCs) was approximately 25 to 30 times as great in the expansion culture group as in the non-expansion group. Adhered EPCs had endothelial cell features, including the expression of CD31, Kinase domain region, von Willebrand factor, vascular endothelial-cadherin, positive for Ulex europeus agglutinin I staining, and up-take of acetylated low-density lipoprotein. Adhered EPCs secreted 6-keto-prostaglandin F(1alpha) identically to that secreted by human umbilical vein endothelial cells (HUVECs). The cells also expressed messenger RNA for phospholipase A(2), cyclooxygenase (COX)-1, COX-2, prostaglandin I(2) synthase, tissue plasminogen activator, and thrombomodulin (TM). TM protein in adhered EPCs properly activated protein C. Scanning electron microscopy revealed the suppression of platelet adhesion and aggregation on the surface of cell monolayer. Adhered EPCs treated with 50 microg/mL of cytochalasin B induced a larger diameter and a greater number of fenestrae, subsequently producing significantly more ultrafiltration than the non-treated cell. These results suggest that CD133(+) EPCs would potentially be applicable in bioartificial glomerulus.

Suppression of parathyroid hormone production in vitro and in vivo by RNA interference.

We used RNA interference, which causes sequence-specific degradation of target mRNAs to suppress the production of parathyroid hormone by cells of patients with secondary hyperparathyroidism in vitro and in vivo. Transfection of small interfering RNA (siRNA) against human parathyroid hormone into monolayers of parathyroid cells cultured from these patients caused a dose-dependent decrease of secretion and mRNA levels with 80% or more suppression using 40 nM siRNA. Parathyroid cells cultured on non-adherent plastic produced spheroid cell aggregates which secreted parathyroid hormone for more than 150 days. Transfection of these spheroids with 50 nM targeted siRNA decreased parathyroid hormone production to 20% of the control level, with half of them being suppressed for 50 days. When parathyroid cells were transplanted into the livers of athymic nude mice, plasma human parathyroid hormone rose to 100-300 pg/ml within one month and remained at about this level for at least 39 days. Systemic delivery of hormone-targeted siRNA into these mice caused a dose-dependent suppression of circulating human parathyroid hormone for at least one month, with a maximum 80% suppression achieved by 80 microg of siRNA. Our study shows that hormone secretion by parathyroid cells of patients with secondary hyperparathyriodism can be suppressed both in vitro and in vivo by targeted siRNAs.

Enhancement of permeability in endothelial cells for the development of an antithrombogenic bioartificial hemofilter.

For the development of an antithrombogenic bioartificial hemofilter, in which the inner surface of hollow fibers is lined by endothelial cells, it is essential to increase the permeability of the cells in order to achieve a sufficient ultrafiltrate. We tried to increase it by using an actin microfilament polymerization inhibitor, cytochalasin B (CyB). Fifty microg/mL CyB was added for 2 h to the culture medium of confluent rat glomerular endothelial cells (RGEC) and human umbilical vein endothelial cells (HUVEC). Under the 130 mmHg hydrostatic pressure, the CyB-treated group produced significantly more ultrafiltration than the non-treated control group and this increase was maintained for at least 7 days. Horseradish peroxidase (HRP) permeability acutely and reversibly increased in the CyB-treated group compared with the non-treated control group. Scanning electron microscopy revealed a larger average diameter and increased number of fenestrae on the CyB-treated endothelial cells, compared with the non-treated cells. This phenomenon also lasted for at least 7 days. The platelet adherence test showed that CyB did not deteriorate the antithrombogenic property of endothelial cells. These results indicate that CyB is potentially applicable for the enhancement of endothelial cell permeability in an antithrombogenic bioartificial hemofilter.

Prevention of LLC-PK(1) cell overgrowth in a bioartificial renal tubule device using a MEK inhibitor, U0126.

A common approach to construct a bioartificial renal tubule system is to utilize renal tubular cells seeded in porous polymer membrane hollow fibers. We have reported that overgrowth of renal tubular cells was not beneficial for the transport and reabsorption functions of bioartificial tubules. Therefore, long-term maintenance of a confluent monolayer of cells in hollow fibers is essential and technically challenging. In this study, we examined whether MEK inhibitor, U0126, could maintain the monolayer of Lewis-lung cancer porcine kidney 1 (LLC-PK(1)) cells on polystyrene plates and in a dialysis module housing hollow fibers made of ethylene vinyl alcohol (EVAL). We also evaluated the leakage of urea nitrogen (UN) and creatinine (Cr) through the cell-lined hollow fibers, and reabsorption of glucose and sodium by the cells, comparing the U0126-treated cells with nontreated cells in the module. Treatment with 50micromol l(-1) U0126 prevented the overgrowth of cells cultured on polystyrene plates. Moreover, U0126-treatment reduced the leakage of UN, and increased the reabsorption of electrolytes in 65cm(2) modules. Scanning electron microscopy revealed that it also prevented the overconfluence of cells in modules. Therefore, application of U0126 is a potentially effective method to improve the performance of the device.

Prognostic value of serum cardiac troponin I in ambulatory patients with chronic renal failure undergoing long-term hemodialysis: a two-year outcome analysis.

OBJECTIVES: We sought to evaluate the prognostic value of cardiac troponin I (cTnI) in asymptomatic, ambulatory patients with chronic renal failure treated with long-term hemodialysis. BACKGROUND: Smaller, short-term follow-up studies on this subject have given conflicting results. METHODS: A total of 126 ambulatory patients with chronic renal failure treated with long-term hemodialysis were followed for two years for all-cause mortality, cardiac mortality, all-cause hospital admissions and cardiac hospital admissions. Serum cTnI was measured before dialysis at the time of study entry. RESULTS: One hundred two patients had normal serum levels of cTnI (< or =0.03 ng/ml) and 24 patients had elevated levels (0.015 +/- 0.007 vs. 0.053 +/- 0.029 ng/ml, p < 0.0001). No significant difference in all-cause mortality (20 vs. 4 deaths), cardiac mortality (4 vs. 1 death), all-cause hospital admissions (1.74 +/- 1.72 vs. 1.25 +/- 1.19 admissions/patient) or cardiac admissions (0.52 +/- 0.89 vs. 0.33 +/- 0.76 admissions/patient) was present between the patients with normal cTnI levels and those with elevated cTnI levels. Serum cTnI was not significantly different between patients who died versus those who survived (0.022 +/- 0.019 vs. 0.022 +/- 0.021 ng/ml). Serum cTnI was not an independent predictor of all-cause mortality, cardiac mortality, all-cause admissions or cardiac admissions. Age (older) and serum albumin (lower) were independent predictors of all-cause mortality, whereas a history of myocardial infarction was an independent predictor of cardiac mortality. Serum sodium (lower) was an independent predictor of all-cause hospital admissions, whereas hypertension and previous myocardial infarction were independent predictors of cardiac admissions. The best predictors of the time to death were age (older) and serum sodium level (lower), irrespective of the serum cTnI levels. CONCLUSIONS: Cardiac troponin I has a limited role in predicting mortality and hospital admissions in asymptomatic patients with chronic renal failure treated with long-term hemodialysis.

Myocardial infarction with normal coronary arteries: the pathologic and clinical perspectives.

Myocardial infarction with normal coronary arteries is a syndrome resulting from numerous conditions but the exact cause in a majority of the patients remains unknown. Cigarette smokers and cocaine users are more prone to develop this condition. The possible mechanisms causing myocardial infarction with normal coronary arteries are hypercoagulable states, coronary embolism, an imbalance between oxygen demand and supply, intense sympathetic stimulation, non-atherosclerotic coronary diseases, coronary trauma, coronary vasospasm, coronary thrombosis, and endothelial dysfunction. It primarily affects younger individuals, and the clinical presentation is similar to that of myocardial infarction with coronary atherosclerosis. Thrombolytics, aspirin, nitrates, and beta blockers should be instituted as a standard therapy for acute myocardial infarction. Once normal coronary arteries are identified on subsequent angiography, the calcium channel blockers could be added since coronary vasospasm appears to play a major role in the pathophysiology of this condition. The beta blockers should be avoided in cocaine-induced myocardial infarction because the coronary spasm may worsen. In myocardial infarction with normal coronary arteries, complications such as malignant arrhythmia, heart failure, and hypotension are generally less common, and prognosis is usually good. Recurrent infarction, postinfarction angina, heart failure, and sudden cardiac death are rare. Stress electrocardiography and imaging studies are not useful prognostic tests and long-term survival mainly depends on the residual left ventricular function, which is usually good.

RBF networks for source localization in quantitative electrophysiology.

The backpropagation neural network methods have been proposed recently to solve the inverse problem in quantitative electrophysiology. A major advantage of the technique is that once a neural network is trained, it no longer requires iterations or access to sophisticated computations. We propose to use RBF networks for source localization in the brain, and systematically compare their performance to those of Levenberg-Marquardt (LM) algorithms. We show the use of two types of Radial Basis Function Networks (RBF) network: a classic network with fixed number of hidden layer neurons and an improved network, Minimal Resource Allocation Network (MRAN), recently proposed by one of the authors, capable for dynamically configuring its structure so as to obtain a compact topology to match the data presented to it.

Acute myocardial infarction with angiographically normal coronary arteries.

The exact etiology of myocardial infarction remains unknown in a majority of the patients with normal coronary arteries. Those who smoke cigarettes and use cocaine are more prone to have this condition. The possible mechanisms underlying myocardial infarction with normal coronary arteries are hypercoagulable states, coronary embolism, an imbalance between oxygen demand and supply, nonatherosclerotic coronary diseases, coronary trauma, coronary vasospasm, and coronary thrombosis. Myocardial infarction with normal coronary arteries primarily affects younger persons and is distinctly rare in patients older than 50 years. We describe a case of acute myocardial infarction with normal coronary arteries in a 61-year-old woman who smoked cigarettes. The clinical perspectives and management of the myocardial infarction with normal coronary arteries are discussed.

Elevation of serum cardiac troponin I in noncardiac and cardiac diseases other than acute coronary syndromes.

This study evaluated the role of serum cardiac troponin I as a biochemical marker for the diagnosis of acute coronary syndromes in the presence of noncardiac diseases. Diagnostic characteristics were examined in 102 consecutive patients who were found to have serum cardiac troponin I levels higher than the upper reference limit of 0.6 ng/mL. Of 102 patients with cardiac troponin I levels of >0.6 ng/mL, 35 did not have the final diagnoses of acute coronary syndromes (myocardial infarction or unstable angina) but had various other final diagnoses, including nonischemic dilated cardiomyopathy, muscular disorders, central nervous system disorders, HIV disease, chronic renal failure, sepsis, lung diseases, and endocrine disorders. The mean value of serum cardiac troponin I in the patients with diseases other than acute coronary syndromes was significantly lesser than in those with acute coronary syndromes (2.0+/-1.9 [SD] v. 24.7+/-28.2 ng/mL; P<.0001). There were significantly fewer histories of chest pain and prior myocardial infarction in patients with diseases other than acute coronary syndromes than in those with acute coronary syndromes (history of chest pain, 3 v. 48 patients [P<.001]; history of prior myocardial infarction, 0 v. 30 patients [P<.001]). In conclusion, elevated serum levels of cardiac troponin I, especially in the lower ranges, should be interpreted with caution, particularly in patients suffering from acute illnesses who lack other diagnostic features suggestive of acute coronary ischemic events.

Increased regional and transmyocardial dispersion of ventricular repolarization in end-stage renal disease.

BACKGROUND: Approximately half of patients with end-stage renal disease die because of cardiac disease, and ventricular arrhythmias are the common terminal events. Increased dispersion of the repolarization phase of the myocardial action potential can predispose patients to ventricular tachycardia and fibrillation causing cardiac death. OBJECTIVE: To determine the existence of increased regional and transmyocardial dispersion of ventricular repolarization in end-stage renal disease. STUDY DESIGN: Case-control prospective study. PATIENTS AND METHODS: The QT dispersion and the interval between the peak of the T wave (Tp) and the end of the T wave (Te) on a surface electrocardiogram represent regional and transmyocardial dispersion in ventricular repolarization, respectively. The prehemodialysis QT dispersions and Tp-Te intervals of 94 consecutive patients with end-stage renal disease were determined and compared with those of age- and sex-matched healthy controls. RESULTS: Both the QT and the QTc dispersion were significantly higher in the end-stage renal disease group than in the control group (QT dispersion 46 +/- 17 ms [mean +/- SD] versus 26 +/- 16 ms, P < 0.001; QTc dispersion 51 +/- 20 ms versus 30 +/- 20 ms, P < 0.001). Similarly, both the corrected average Tp-Te and the corrected maximum Tp-Te intervals were significantly higher in the end-stage renal disease group than in the control group (corrected average Tp-Te interval 99 +/- 19 ms versus 87 +/- 19 ms, P = 0.023; corrected maximum Tp-Te interval 114 +/- 23 ms versus 103 +/- 23 ms, P = 0.023). CONCLUSIONS: Increased regional and transmyocardial dispersion of ventricular repolarization in end-stage renal disease was demonstrated. This increased dispersion may be a contributory factor in the high cardiac mortality in patients with end-stage renal disease.

Specificity of cardiac troponin I and creatine kinase-MB isoenzyme in asymptomatic long-term hemodialysis patients and effect of hemodialysis on these cardiac markers.

OBJECTIVES: The objectives of this study were: (1) to evaluate the specificity of cardiac troponin I and creatine kinase-MB isoenzyme in ambulatory asymptomatic chronic renal failure patients on long-term hemodialysis, and (2) to evaluate the effect of hemodialysis on the serum levels of cardiac troponin I and creatine kinase-MB isoenzyme. METHODS: One hundred and forty-four consecutive ambulatory asymptomatic chronic renal failure patients on hemodialysis for a minimum of 1 year were evaluated clinically. Serum cardiac troponin I and creatine kinase-MB isoenzyme levels were measured with specific monoclonal antibodies before and after dialysis using ACCESS Troponin I and ACCESS CK-MB assays. RESULTS: The specificity of serum cardiac troponin I was 83% with a cutoff level of 0.03 ng/ml, which is an expected level for healthy population, but it rose to 100% with a cutoff level of 0.15 ng/ml, which is a reference level for patients with acute myocardial infarction. Twenty-four (17%) patients had borderline elevation in cardiac troponin I (>0.03 to <0.15 ng/ml). A history of angina pectoris was more common in the borderline-elevated cardiac troponin I subgroup. In 28% of the patients, serum creatine kinase-MB isoenzyme levels were increased with a specificity of 72% at a cutoff level of 4 ng/ml, which is the upper limit of normal, but the specificity rose to 98% by increasing the cutoff level value to 10 ng/ml. There were no statistically significant differences in serum levels of cardiac troponin I and creatine kinase-MB isoenzyme before and after dialysis. CONCLUSIONS: Cardiac troponin I is highly specific in ambulatory asymptomatic chronic renal failure patients on long-term hemodialysis; borderline elevations in cardiac troponin I may represent microinjury to the myocardium. A serum level of creatine kinase-MB isoenzyme >2.5 times of the normal upper limit may be highly specific in this patient population. Hemodialysis per se does not significantly change the serum levels of cardiac troponin I and creatine kinase-MB isoenzyme.

Zones of atrial vulnerability. Relationships to basic cycle length.

BACKGROUND: Bradycardia is commonly found in individuals at risk for paroxysmal atrial fibrillation (AF). However, a clear relationship between lengthening of basic cyclic length (BCL) and AF has not been demonstrated. METHODS AND RESULTS: In 20 open-chest dogs, atrial refractoriness, AF vulnerability, and atrial activation times (ACTs) were determined in sinus rhythm and at BCLs of 400, 300, and 200 ms, and the findings at the same coupling intervals and stimulus strengths were compared. As BCL increased, AFV zone lengthened, and its outer limit occurred later in diastole. The outer limit of the AF vulnerability zone for a BCL was its relative refractory period; the inner limit, however, was not its effective refractory period. A border zone, defined by the inner limit of the AF vulnerability zone and the effective refractory period for a BCL, decreased as BCL lengthened, offsetting the increase in the AF vulnerability zone. The border zone was characterized by paradoxical stimulus current strength propagation relations and features suggesting supernormal conduction. ACT also increased with BCL lengthening. When AF induced by rapid atrial burst pacing was contrasted with AF induced by an extrastimulus, it tended to have a more disorganized pattern and lasted longer. CONCLUSIONS: Lengthening of BCL increases the AF vulnerability zone, extending its outer limit later in diastole and comprising an increasing component of the total duration of the relative refractory period. Very short BCLs create conditions that also favor AF vulnerability.

An analysis of the factors which impinge on a nurse's decision to enter, stay in, leave or re-enter the nursing profession.

As part of a wider study concerned with the changing nurse employment patterns a detailed questionnaire was completed by a total of 2325 qualified female nurses, 841 of whom were working fulltime in nursing, 634 were inactive, 678 were offering their services on a part-time basis and 172 were working in some other occupation. In a previous article the results of the analysis conducted on the responses to the attitude questions were presented. In this paper the replies to those questions aimed at soliciting the reasons felt to have impacted on the respondent's decision to take up nursing, to stay or to leave the profession and to re-enter the profession are analysed. As the questionnaires were distributed in the course of two projects separated by 4 years, what is of particular interest is the similarity of the two sets of results. These indicate that there is still a very high level of job satisfaction as evidenced by the extent to which nursing would be recommended to a friend or relative. The primary obvious reason for inactivity is the existence of a young child but when further intentions are explored it is clear that there is a large pool of qualified nurses keen to resume a career the main obstacle being the lack of sufficient flexibility of hours of working.

Attitudes of 2325 active and inactive nurses to aspects of their work.

As a part of an ongoing larger study concerned with nurse manpower planning, an attempt has been made to investigate the reasons for the non-participation in the labour force of such a large proportion of qualified nurses. In an attempt to collect information on this topic a questionnaire was developed and distributed to a sample of nurses. The article describes in some detail the two different ways in which the names and addresses of the sample were generated. The first method involved making contact by the simple expedient of dropping leaflets through letterboxes while the second involved tracing respondents through their last known address when they originally qualified. The success of these two approaches is contrasted which should be of value to anyone contemplating a similar name-capturing exercise. A total of 2325 questionnaires were returned and computer analysed. This article presents the results of one part of that analysis i.e. the factor analysis conducted on the attitudinal questions contained in the document. A five-factor solution yielded highly interpretable results and the factor loadings are presented along with the pattern of responses. The factor scores are then contrasted for three different groups of respondents: the grouping being based on whether the respondent was working full-time, part-time or not at all.