Defective erythropoietin production and reticulocyte response in acute Plasmodium falciparum malaria-associated anemia.

To elucidate the relationship between falciparum malaria-associated anemia and serum erythropoietin (Epo) levels and reticulocyte response during acute malaria infection, 87 adults aged 18-65 years presenting with acute, uncomplicated malaria were examined on enrollment and for 28 days of follow-up. The 87 patients were divided into 2 groups: those with anemia (n = 45) and those without (n = 42). Serum samples were taken on admission (Day 0), then on Days 7, 21, and 28, to measure the reticulocyte count, absolute reticulocyte count, reticulocyte hemoglobin content, and erythropoietin level (Epo). The absolute reticulocyte counts for the anemic patients were significantly higher than for those without anemia on Days 0, 7, 21, and 28. The serum Epo levels for the anemic patients were significantly higher than the non-anemic group only on Day 0 (44.39 +/- 4.06 vs 25.91 +/- 4.86 mlU/ml, p < 0.001). Inadequate Epo production was found in 31.03% (27/87) of patients on Day 0, 37.93% (33/87) on Day 7, 43.67% (38/87) on Day 21, and 39.08% (34/87) on Day 28. These results indicate defective Epo production and reticulocyte response in adult patients suffering from acute P. falciparum malaria, which differs from pediatric patients. Our findings may provide the basis for further study into the choice of therapeutic strategies to treat acute P. falciparum malaria-associated anemia with recombinant human Epo to correct refractory anemia due to malaria.

Analysis of polymorphisms in the 5'-flanking region of the apolipoprotein(a) [Apo(a)] gene in Thai subjects with coronary artery diseases.

Lipoprotein(a) [Lp(a)] is a complex lipoprotein particle in human plasma. It is composed of apolipoprotein B (Apo B)-100 and apolipoprotein(a) which are linked by a disulfide bond. Plasma levels of the Lp(a) vary greatly (over 1,000 folds) among individuals. Elevated plasma levels of the Lp(a) have been shown to be an independent risk factor for coronary artery diseases (CAD). The level of Lp(a) is controlled by a single gene, the Apo(a) gene, with multiple alleles; each encodes different concentrations of the Lp(a). Previous studies revealed the presence of polymorphisms in the 5'-flanking region (FL) of the Apo(a) gene at 3 positions: G or A (-914), C or T(-49), and G or A (-21), which can be detected by cleavage of PCR-amplified DNA products with TaqI, MaeII and HhaI, respectively. The 5'-FL genotypes of the Apo(a) gene can be classified by the combination of the presence (+) or absence (-) of these restriction sites into 5 types; type A, +++, type B, -++, type C, -+-, type D, --+ and type E, +-+. In the present study, the authors analyzed the 5' FL types of the Apo(a) gene by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) in 100 healthy control subjects, 26 CAD patients with [Lp(a)] < or = 30 mg/dL, and 94 CAD patients with [Lp(a)] > 30 mg/dL. The authors found that the genotype frequencies of the Apo(a) gene were 53, 16, 27 and 4%, for types A, B, C and D respectively in normal healthy controls. In CAD patients with [Lp(a)] < or = 30 mg/dL, the distribution of the genotype frequencies were 53.8, 11.5, 30.8 and 3.9% for types A, B, C and D, respectively. Additionally in CAD patients with [Lp(a)] > 30 mg/dL, the genotype frequencies were 60.6, 11.7, 21.3 and 6.4% for types A, B, C and D, respectively. The present study might shed some light to understand CAD at the molecular level.

Effect of short-term folate and vitamin B supplementation on blood homocysteine level and carotid artery wall thickness in chronic hemodialysis patients.

OBJECTIVE: Hyperhomocysteinemia is an independent risk factor for atherosclerotic vascular disease in chronic hemodialysis patients. This stratified randomized controlled trial was designed to measure the effect of high dose oral vitamin B6, vitamin B12, and folic acid on homocysteine levels, and to evaluate the effect on atherosclerosis as measured by Intima-Media Thickness (IMT) of carotid arteries. MATERIAL AND METHOD: Fifty-four chronic hemodialysis patients with hyperhomocysteinemia were randomized to receive oral 15 mg folic acid, 50 mg vitamin B6, and 1 mg vitamin B12 daily (treatment group) or oral 5 mg folic acid alone (control group) for 6 months. Homocysteine level and IMT were measured in both groups. RESULTS: At 6 months, homocysteine levels in the treatment group were significantly reduced from 27.94 +/- 8.54 to 22.71 +/- 3.68 mmol/l (p = 0.009) and were not significantly increased from 26.81 +/- 7.10 to 30.82 +/- 8.76 mmol/l in control group (p = 0.08). Mean difference between both groups was statistically significant (p = 0.002). There was no significant difference of IMT of carotid arteries, however, a tendency that the treatment group would have less thickness was observed (0.69 +/- 0.29 mm and 0.62 +/- 0.16 mm, p = 0.99). CONCLUSION: Treatment of hyperhomocysteinemia in chronic hemodialysis patients with daily oral 15 mg folic acid, 50 mg vitamin B6, and 1 mg vitamin B12 for 6 months decreases homocysteine levels and tends to reduce IMT of carotid arteries. A long term study for the prevention of atherosclerosis is warranted.

Relationship between hyperhomocysteinemia and atherosclerosis in chronic hemodialysis patients.

BACKGROUND: Hyperhomocysteinemia is an independent risk factor of coronary artery heart disease (CAHD) and atherosclerosis in a normal population. However, it is still controversial in end-stage kidney disease patients who underwent long-term dialysis. Carotid intima-media thickness (IMT) is the standard non-invasive measurement of atherosclerosis. The aims of the present study were to determine the homocysteine (Hcy) level, and to evaluate its role as a risk factor of atherosclerosis in hemodialysis (HD) patients. MATERIAL AND METHOD: Clinical data and blood chemistries were assayed in 62 HD patients. Atherosclerosis was defined by clinical presentations of CAHD, cerebrovascular or peripheral vascular diseases, or carotid plaque by ultrasound. IMT was also measured by ultrasound RESULTS: Plasma Hcy level in HD patients was significantly higher in HD patients than normal controls (28.3 +/- 8.3 vs 9.7 +/- 2.9 micromol/l, p < 0.001). Older age (p < 0.001), male sex (p = 0.05), longer duration of HD (p = 0.05), and higher plasma Hcy level (p = 0.01) correlated with atherosclerosis by univariate analysis, but plasma Hcy did not show significant correlation by multivariable analysis. There was also correlation between IMT and atherosclerosis in HD patients (p < 0.001) but no correlation was observed between plasma Hcy level and lMT. CONCLUSION: Hyperhomocysteinemia is not an independent factor in the genesis of atherosclerosis in HD patients. Advanced age plays a major role of hyperhomocysteinemia and IMT is a useful marker of atherosclerosis in these patients.

Serum N-terminal pro-brain natriuretic peptide in normal Thai subjects.

Aminoterminal portion of pro-brain natriuretic peptide (NT-proBNP) appears to be useful in the screening, diagnosis and prognosis of left ventricular dysfunction and congestive heart failure. The purpose of this study was to determine the values of serum NT-proBNP in normal Thai subjects compared with subjects from other countries. The design is a cross sectional study. The authors enrolled 243 consecutive healthy subjects (134 males and 109 females) from the checkup department of Bangkok Hospital for NT-proBNP measurement. The serum fraction was measured for NT-proBNP concentration by using Elecsys 2010 (Roche Diagnostics, Switzerland). The concentrations of NT-proBNP in normal Thai subjects were 33.30 +/- 35.43 pg/ml. The NT-proBNP levels increased with age (age < or = 50 years = 27.56 + 28.77 pg/ml and age > 50 years = 47.20 +/- 45.18 pg/ml, p < 0.001). Females usually have higher NT-proBNP than males (females = 40.42 +/- 31.59 pg/ml, males = 27.51 +/- 37.40 pg/ml, p = 0.0045). This study established the NT-proBNP concentrations in normal Thai subjects, which were not different from other studies. The authors suggested the normal cut-off values for subjects aged < or = 50 years should be 100 pg/ml and the normal cut-off values for subjects aged > 50 years should be 200 pg/ml. The NT-proBNP assay could be used as a rule out marker for heart failure in patients and may trigger further cardiac investigation.

Circulating N-terminal pro-brain natriuretic peptide and cardiac troponin T in chronic dialysis patients.

In the general population, plasma concentrations of cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptides (NT-proBNP) are useful as markers of cardiac ischemia and heart failure respectively. Whether these cardiac markers have similar diagnostic potential in chronic dialysis patients are not known. The authors studied the diagnostic value of cTnT and NT-proBNP correlated with the clinical status of 63 chronic renal failure (CRF) patients with chronic dialysis (30 males and 33 females), aged 26 to 77 years (mean +/- SD, 55.9 +/- 12.6 years). Plasma cTnT and NT-proBNP were determined by using Elecsys 2010 (Roche, Switzerland). The authors found that 23.8 per cent of the chronic dialysis patients had cTnT concentrations more than the cut-off (> or = 0.1 ng/ml) and 100 per cent of these patients had NT-proBNP concentrations over the cut-off (> 334 pg/ml). The authors could not demonstrate the statistical difference between males and females for NT-proBNP concentrations as reported in the general population. But cTnT concentrations in females were significantly less than males. The authors also found a weak correlation between the two markers, when the circulating cTnT was correlated with NT-proBNP. These results suggested that plasma cTnT in chronic dialysis patients should be a prognostic marker for cardiac ischemia by using the same cut-off as the normal population. However, plasma NT-proBNP concentrations could not be used as a heart failure marker in this group of patients and needed another cut-off value for specific use in chronic dialysis patients. Moreover, the combination of cTnT and NT-proBNP concentrations in these patients may be another choice for detection of both cardiac ischemia and heart failure in the same situation. These combination markers should improve mortality in chronic dialysis patients.

Role of the plasma brain natriuretic peptide in differentiating patients with congestive heart failure from other diseases.

BACKGROUND: Heart failure (HF) is primarily a disease of the elderly. The incidence of congestive heart failure (CHF) in Thailand has been increasing during the last 10 years. Unlike other diseases, physicians have only rough patients' symptoms and physical findings to guide the adequacy of treatment. Recently, there has been evidence of the role of brain natriuretic peptide (BNP) and its use in HF concerning diagnosis, prognosis, and treatment follow-up. The purpose of this study was to determine the sensitivity and specificity of N-terminal part of brain natriuretic peptide plasma level (NT-proBNP) in the diagnosis of HF in Thai patients who presented with dyspnea. METHOD: The design was a cross sectional study. The authors enrolled 50 consecutive patients from the Respiratory Unit with dyspnea from chronic obstructive pulmonary disease (COPD), asthma, or anxiety. The cardiovascular cause of dyspnea such as pulmonary emboli and poor left ventricular ejection fraction (LVEF) were excluded. Forty eight consecutive patients with evidence of HF who presented to the Cardiac Center with a history of dyspnea on exertion were assigned as cases. Five milliliters of venous blood samples were taken and sent together with 200 samples from a normal healthy population from the check up department for NT-proBNP measurement. RESULTS: In case and control groups, there were no statistical significances in sex (males 68.8% vs females 52.0%, p > 0.05) and age (63.3 +/- 14.9 vs 55.6 +/- 16.9; p > 0.05). The mean left ventricular ejection fraction in the case group was 32.4 +/- 9.7 per cent. There was significant difference between value of NT-proBNP in the control group (386 +/- 1,041 pg/ml) and in the case group (8,912 +/- 12,525 pg/ml, p < 0.001). To diagnose HF in patients who presented with dyspnea using the cut-off value of NT-proBNP at > 150 pg/ml in patients with dyspnea the sensitivity was 96 per cent, and the specificity of 72 per cent; at > 200 pg/ml the sensitivity was 96 per cent and the specificity was 80 per cent and at > 300 pg/ml the sensitivity was 94 per cent and specificity of 82 per cent. Plasma level of NT-proBNP increased significantly with increasing New York Heart Association (NYHA) functional class (class II: 1,107 +/- 1,091 pg/ml; class III: 5,097 +/- 4,201 pg/ml, class IV: 19,389 +/- 15,966 pg/ml p < 0.01). There was no significant difference of plasma NT-proBNP levels in patients with ischemic (8,586 +/- 11,601 pg/ml; n = 35) and those with non ischemic cardiomyopathy (9,789 +/- 15,229 pg/ml; n = 13). Plasma NT-proBNP was associated with neck vein distension (p < 0.05) but there was no significant association with S3, paroxysmal nocturnal dyspnea, rales, cardiomegaly, acute pulmonary edema, serum sodium (r = 0.22), ejection fraction (r = -0.18) and subsequent hospital death (p > 0.05). CONCLUSION: Measurement of plasma NT-proBNP proved to be a useful diagnostic test in differentiating HF from other causes in patients who presented with dyspnea.

Assessment of radiofrequency current-induced myocardial damage based on analysis of cardiac troponin T serum concentration.

The present study investigated the effect of radiofrequency (RF) current energy energy on the release pattern of myocardial marker proteins in 44 patients undergoing RF catheter ablation of supraventricular and ventricular tachycardia serial measurements of the activity of enzyme creatine kinase (enzymatic method), CK-MB isoneration TnT Enzymum ELISA, Boehringer Mannheim). The results showed that nearly all (91 percent) of the patients studied demonstrated a significant elevation in cTnT concentration following transcatheter applications of RF energy, whereas only 12 (27 percent) and 13 (29 percent) patients exhibited a postprocedural increase in CK and CK-MB activity, respectively. In contrast to the variable time for peak activity of CK and CK-MB, 40 of the 44 patients displayed an early peak cTnT concentration at eight hours after the procedure with a subsequent decline thereafter. Levels of cTnT and, to a lesser extent, CK but not CK-MB activity corressory pathways or atrioventricular nodal reentrant tachycardia. In conclusion, cardiac troponin T is a more sensitive indicator of RF energy-induced myocardial injury and has a more uniform pattern of myocardial release than the conventional CK and CK-MB. Determinations of cTnT serum concentration may thus provide a reliable method for assessing the extent of myocardial damage and for monitoring complications developed after radiofrequency or other froms of treascatheter ablation procedures.

Cyclosporine monitoring in patients with renal, cardiac and bone marrow transplants: A comparison between clone enzyme donor immunoassay and fluorescence polarization immunoassay methods.

In the present study a new method for selectively determining parent cyclosporine in whole blood, a clone enzyme donor immunoassay (CEDIA; Boehringer Mannheim), was compared with a fluorescence polarization immunoassay (FPIA; TDxAbbott). A total of 429 samples were collected, comprising 371 renal, 34 cardiac, 14 bone marrow and 10 corneal transplant recipients. Regression equations in 429 samples is CEDIA cyclosporine (ng/mL) = 0.999 x FPIA (ng/mL) + 1.684, (r=0.997). The linearity analysis was done from 0 – 1,000 ng/mL, which gave a good analytical range of between 15-600 ng/mL. The new CEDIA method also has within-rin CV = 1.77 – 3.69 percent which is better than the FPIA method (2.20 – 6.10 percent). The advantages of the new CEDIA method are the lower cost of the reagents and the fact that there is no need to purchase a new automated clinical chemistry analyser since it can be applied to routine chemistry instruments immediately after the reagents become available to the laboratory.

Glucose dehydrogenase biosensor for glucose monitoring: An accurate oxygen-insensitive electrochemical biosensor.

In severely hypotensive patients, fingerstick glucose determinations often do not accurately represent venous glucose levels. Those fingerstick glucose values that fall outside the acceptable range in hypotensive patient group are all lowere than the standard glucose values because the strip used is the oxygen-sensitive glucose oxidase method. This condition will be incorrectly diagnosed as a hypoglycaemic condition instead of normal. The objective of this study was to evaluate the O2-insensitivity of a new electrochemical biosensor test strip that can be used for different types of blood samples. This biosensor uses an O2-independent glucose dehydrogenase enzyme instead of an O2-dependent glucose oxidase enzyme in the reaction. We compared glucose measurements between venous blood by biosensor with the standard method which gave a coefficient of correlation (r)=0.998 (n=216). In cases of arterial blood with a wide range of pO2 varying from 21.7 mmHg to 388.7 mmHg, we compared the glucose levels measured by biosensor with standard method which gave r=0.997 (n=148). The precision analysis was tested in three glucose levels and gave a coefficient of variation (CV) less than 3 percent. The results showed that the new electrochemical biosensor was oxygen-insensitive and provided rapid, precise and accurate glucose measurements.

Analytical performance of direct LDL-cholesterol assay compared with friedewald LDL-cholesterol and apolipoprotein B assay.

Clinical laboratory currently estimate low-density lipoprotein cholesterol using the Friedewald formula, which requires fasting specimens and is subject to error with increasing triglyceride levels. The direct LDL Immunoseperation Reagent for LDL-cholesterol assay also have some disadvantages: 1. pipetting sample, 2. mixing and 3. centrifugation before subsequent measurement of cholesterol by conventional assay. We describe a rapid non-percipitating LDL-cholester assay using tentaclepolynion (PAMPS) reagent which base on precision with within-run and run-to-run coefficients of variation less than 3%. Results are in good agreement with the apolipoprotein assay (direct LDL-C = 1.745 apolipoprotein B-49.764 mg/dL, r=0.805) and also show very good linear regression with Friedewald LDL-C which triglyceride level below 400 mg/dL (Friedewald LDL-C=0.978 direct LDL-C-1.616 mg/dL, r=0.968). This method overcomes drawbacks the Friedewald formula and appears to be useful tool in managing hyperlipidemic patients by using an accurate quantification of LDl-C in the routine laboratory.

Lipoprotein and apolipoprotein profile in children with primary nephrotic syndrome: Metabolic alterations and consequences.

Serum levels of lipoprotein and apolipoprotein from 50 children, aged between 2 and 16 years, were measured by the enzymatic method and by immunoturbidimetric assay respectively, to determine abnormalities of lipid metabolism during the course of primary nephritic syndrome. There was a highly significant correlation between serum levels of both total cholesterol and low density lipoprotein cholesterol (LDL-C) and those of apolipoprotein B (apo B) (n=114, r=0.946, p<0.001 and n=99, r=0.943, p<0.001, respectively) and, to a lesser extent, between serum high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (apo A-I) levels (n=123, r=0.679, p<0.001). HDL-C levels of apo A-I did not exhibit an association with those of albumin. The ratio of HDL-C to apo A-I, on the other hand, was low (<1.0) at very low levels of serum albumin (<2.0 g/dI) but showed a gradual rise with increasing albumin levels. These results may indicate a compositional change in HDL particles in the clinical course of nephritic syndrome, with a relatively high level of apolipoprotein-rich HDL particle (HDL)3 at very low albumin levels and predominantly HDL2 particles, which contain relatively more cholesterol, at increasing levels of albumin. Serum levels of LDL-C and apo B correlated significantly and inversely with serum albumin levels (n=101, r=-0.836, p<0.001 and n=114, r=-0.825, p<0.001, respectively). Compared with levels from healthy control children (2.52+0.67 mmol/L (97+26 mg/dI) and 0.86+0.21 g/L) matched for age and serum albumin levels, however, a relatively high concentration of both parameters of 3.59+1.02 mmol/L (139+40 mg/dI) and 1.47+0.32 g/L, respectively, was still observed at high serum albumin levels (> 4 g/dI). The finding of a persistance of abnormalities in lipid profile, despite a response to treatment of nephritic syndrome, may have some prognostic significance and should been given therapeutic consideration in the long-term management of children with primary nephrotic syndrome.

Direct measurement of high-density lipoprotein cholesterol compared with the precipitation-based methods.

We compared the performance of the direct measurement for quantifying high-density lipoprotein cholesterol (HDL-C) with the precipitation-based method for HDL-C, using samples with a wide range of HDL-C concentrations (7-144 mg/dL). The coefficient of correlation for the two methods was 0.98 (n=500). Both methods were precise with a run-to-rum CV of < 4.4 per cent. By using direct measurement for HDL-C we can reduce errors which occurred in the precipitation-based method, especially from centrifugation and recovery of the supernatant. The direct measurement method strongly appears to successfully discriminate between the serum HDL fractions and completely measures the HDL-C.

Sterility and storage period of placental blood from neonates delivered by caesarian section.

A prospective study was conducted to evaluate the storage period and sterility of placental blood from neonates delivered by caesarian section. Following caesarian section of the infant and placenta, the placenta was immediately placed in a sterile tray and the umbilical cord near the clamps was rinsed with sterile saline and cut 2 cm below the clamps with sterile scissors. An Fr 8 feeding tube was inserted into an umbilical vein and 43 ml of placental blood was drawn into a 50 ml disposable syringe which contained 7 mls of CPDA-1 solution. Five-ml aliquots of blood retrieved from the placenta were inoculated into aerobic and anaerobic blood culture bottles. Sixty-four specimens of CODA-1 anticoagulant blood were retrieved from the placenta and evaluated for biochemical changes to determine the recommended storage period. The mean plasma potassium concentrations were 4.9 + 1.1, 9.1 + 2.6, 13.1 + 2.0 mM/l at 0, 48 and 72 hours after collection, respectively. The 72-hour potassium concentration was higher than the value in adult whole blood stored for 7 days, which is considered fresh blood and recommended for transfusing newborn infants. The 107 paired aerobic/anaerobic culture specimens showed an overall contamination rate of 13%. These findungs suggest that placental blood in CPDA-1 can be stored for 48 hours for autologous transfusion and that rinsing the umbilical cord in sterile saline cannot prevent bacterial contamination in the retrieved placental blood.