Neuropeptide-Y and atrial natriuretic peptide as prognostic markers in patients on hemodialysis

We conducted a study of the influence of the vasoactive peptides atrial natriuretic peptide (ANP) and neuropeptide Y (NPY) on survival of patients on hemodialysis and their association and relative importance with cardiac and clinical variables. Thirty-three hemodialysis patients were characterized by age, sex, diagnosis, blood pressure, serum (S)-albumin, serum (S)-urea, hemoglobin, dialysis dose, weight gain, duration of dialysis, cardiac hypertrophy, volume, failure, and ischemia and plasma levels of ANP and NPY. The outcomes were analyzed for early deaths (< 1 year) and for all deaths. The association of the variables to early deaths and all deaths, respectively, was studied in Cox proportional hazard analyses. The variables were also studied in three hierarchical steps: clinical variables only, clinical and cardiac variables, and all variables. For all deaths, the independent variables were plasma NPY (pmol/L) (hazard ratio [HR] = 1.035, p = 0.004), heart volume (ml/m2) (HR = 1.009, p = 0.001), and S-albumin (g/L) (HR = 0.750, p = 0.034). For early deaths, the independent variables were predialysis ANP (pmol/L) (HR = 1.008, p = 0.034) and NPY (pmol/L) (HR = 1.031, p = 0.026). In the hierarchical study, excluding the vasoactive peptides, heart volume, heart failure and S-albumin were independently associated with all deaths, and mean arterial blood pressure was associated with early death. When also excluding the cardiac parameters, S-albumin was associated with all deaths and mean arterial blood pressure with early death. In conclusion, plasma levels of the vasoactive peptides ANP and NPY are the most important group in a hierarchy of variables that predict imminent death in hemodialysis patients, and NPY is associated with late death. ANP and NPY apparently sum up the detrimental influence of many factors in hemodialysis patients.     

Comparison of magnesium status using X-ray dispersion analysis following magnesium oxide and magnesium citrate treatment of healthy subjects

The magnesium content in food consumed in the Western world is steadily decreasing. Hypomagnesemia is associated with increased incidence of diabetes mellitus, metabolic syndrome, all-cause and coronary artery disease mortality. We investigated the impact of supplemental oral magnesium citrate versus magnesium oxide on intracellular magnesium levels ([Mg2+]i) and platelet function in healthy subjects with no apparent heart disease. In a randomized, prospective, double-blind, crossover study, 41 (20 women) healthy volunteers [mean age 53±8 (range 31-75) years] received either magnesium oxide monohydrate tablets (520 mg/day of elemental magnesium) or magnesium citrate tablets (295.8 mg/day of elemental magnesium) for one month (phase 1), followed by a four-week wash-out period, and then crossover treatment for one month (phase 2). [Mg2+]i was assessed from sublingual cells through x-ray dispersion (normal values 37.9±4.0 mEq/L), serum magnesium levels, platelet aggregation, and quality-of-life questionnaires were assessed before and after each phase. Oral magnesium oxide, rather than magnesium citrate, significantly increased [Mg2+]i (34.4±3 versus 36.3±2 mEq/L, p<0.001 and 34.7±2 versus 35.4±2 mEq/L, p=0.097; respectively), reduced total cholesterol (201±37 versus 186±27 mg/dL, p=0.016 and 187±28 versus 187±25 mg/dL, p=0.978; respectively) and low-density lipoprotein (LDL) cholesterol (128±22 versus 120±25 mg/dL, p=0.042 and 120±23 versus 121±22 mg/dL, p=0.622; respectively). Noteworthy is that both treatments significantly reduced epinephrine-induced platelet aggregation (78.9±16% versus 71.7±23%, p=0.013 and 81.3±15% versus 73.3±23%, p=0.036; respectively). Thus, oral magnesium oxide treatment significantly improved [Mg2+]i, total and LDL cholesterol compared with magnesium citrate, while both treatments similarly inhibited platelet aggregation in healthy subjects with no apparent heart disease.     

Cardiac calcium evaluation in hemodialysis patients with multisection spiral computed tomography

AIM: The aim of this study is cardiac calcium content evaluation in hemodialysis patients by a new technique, based on ultrafast multisection CT (MTC). METHODS: The study was carried out on 30 HD patients, 14 F and 16 M, average age 57.7 +/- 13.9 years, average HD age 57.3 +/- 47.4 months. The intact PTH levels were 625.4 +/- 571 pg/mL. Serum calcium, phosphate and CaxP product were 9.75 +/- 0.84 mg/mL, 6.21 +/- 1.01 mg/dL and 60.2 +/- 10.7 mg2/dL2, respectively. RESULTS: The values obtained with the MTC technique were reported in terms of Agatson scores. Score values frankly in the pathologic range (>100) were found in 24 patients (80%). Correlation analysis has shown positive and significant correlation coefficients of the score with patients' age (p = 0.003), serum calcium (p = 0.012), CaxP (p = 0.015), iPTH (p = 0.049), and borderline, to HD age (p = 0. 06). CONCLUSION: Risk factors for cardiac calcification are mainly age, degree of hyperparathyroidism, increased CaxP and serum calcium levels. A control of calcium phosphate parameters in hemodialysis patients seems to be mandatory to avoid increased severity of coronary artery disease.     

Effects of oral base therapy on serum ionized calcium, phosphorus and parathyroid hormone in chronic hemodialysis patients

The purpose of this study was to evaluate the effects of oral base therapy on selected chemical parameters in chronic hemodialysis patients. Oral base supplements were administered to 20 acidotic chronic hemodialysis patients for one month. Serum bicarbonate levels rose from 18.6 +/- 2.9 to 22.5 +/- 4.0 mEq/L (p less than 0.0005) and pH rose from 7.35 +/- 0.03 to 7.39 +/- 0.04 (p less than 0.0005). Serum ionized calcium levels fell from 5.03 +/- 0.37 to 4.83 +/- 0.34 mg/dL (1.25 +/- 0.09 to 1.21 +/- 0.08 mmol/L) (p less than 0.01), while intact parathyroid hormone (PTH) levels rose from 547 +/- 697 to 619 +/- 776 pg/mL (p less than 0.05). Base therapy did not result in significant changes in serum levels of total calcium, phosphorus, alkaline phosphatase, urea nitrogen, creatinine, total protein, albumin or potassium. If empiric therapy with exogenous base is given to dialysis patients, ionized calcium levels should be closely monitored since changes in calcium supplement or vitamin D therapy may be required to maintain ionized calcium and parathyroid hormone values at the pre-treatment levels.     

Effects of hemoperfusion on serum cardiac troponin T concentrations using polymyxin B-immobilized fibers in septic patients undergoing hemodialysis

We investigated whether serum cardiac troponin T levels are altered in septic patients undergoing hemodialysis and whether polyinyxin B-immobilized fiber (PMX-F) treatment affects these levels. Fourteen heinodialysis patients with sepsis, 14 hemodialysis patients without sepsis, and 12 age matched healthy controls were included in this study. Cardiac troponin T levels in hemodialysis patients with sepsis (0.56+/-0.28 microg/L) were higher than levels in hemodialysis patients without sepsis (0.16+/-0.06 microg/L, p < 0.01) and healthy control subjects (0.03+/-0.01 microg/L, p < 0.001). The 14 hemodialysis patients with sepsis were randomly assigned to one of two treatment approaches: PMX-F treatment (n = 7) or conventional treatment (n = 7). Plasma endotoxin levels were significantly reduced from 46.6+/-17.8 pg/mI to 8.2+/-2.4 pg/ml, p < 0.01, in patients treated with PMX-F, and serum cardiac troponin T levels were also reduced from 0.62+/-0.30 microg/L to 0.26 = 0.12 microg/L, p < 0.05. Cardiac troponin T levels were unchanged in patients under conventional treatment. These data suggest that cardiac troponin T is indeed elevated in septic patients undergoing hemodialysis and niay reflect subclinical myocardial cell damage. PMX-F is effective in reducing myocardial damage, in part, due to reducing plasma endotoxin levels.     

Changes in serum lipid concentrations during iron depletion and after iron supplementation

To investigate the effects of body iron depletion and iron supplementation on serum lipid concentrations, hematologic indices, iron markers, and serum lipid profiles were measured in 427 girls, age 14-19 yr. There were no significant differences in serum lipid concentrations between subjects with moderate iron deficiency anemia (blood Hb < 12.0 g/dL) and healthy controls. However, serum total cholesterol concentration (mean +/- SD, 148 +/- 16 mg/dL) in severely anemic subjects with blood Hb < 8.0 g/dL was significantly lower than in subjects with blood Hb > or = 14.0 g/dL (170 +/- 17 mg/dL) (p < 0.01). Moreover, serum triglyceride concentration in subjects with blood Hb > 14.0 g/dL was 2-fold higher than in the severely anemic subjects. Mean values of serum total cholesterol and triglyceride (149 +/- 17 mg/dL and 58 +/- 22 mg/dL) in girls with severe anemia were significantly elevated after iron supplementation (164 +/- 17 mg/dL and 98 +/- 26 mg/dL) (p < 0.01, respectively). In the severely anemic subjects, blood Hb concentration was correlated with serum total cholesterol (r = 0.49, p < 0.01) and triglyceride concentrations (r = 0.51, p < 0.01). These findings indicate that severe iron deficiency anemia in girls is attended by decreased concentrations of serum total cholesterol and triglyceride, and that these reduced serum lipid levels return to normal following iron supplementation.     

The effect of iodine restriction on thyroid function in patients with hypothyroidism due to Hashimoto's thyroiditis

Lifelong thyroid hormone replacement is indicated in patients with hypothyroidism as a result of Hashimoto's thyroiditis. However, previous reports have shown that excess iodine induces hypothyroidism in Hashimoto's thyroiditis. This study investigated the effects of iodine restriction on the thyroid function and the predictable factors for recovery in patients with hypothyroidism due to Hashimoto's thyroiditis. The subject group consisted of 45 patients who had initially been diagnosed with hypothyroidism due to Hashimoto's thyroiditis. The subjects were divided randomly into two groups. One group was an iodine intake restriction group (group 1) (iodine intake: less than 100 micro g/day) and the other group was an iodine intake non-restriction group (group 2). The thyroid-related hormones and the urinary excretion of iodine were measured at the baseline state and after 3 months. After 3 months, a recovery to the euthyroid state was found in 78.3 % of group 1 (18 out of 23 patients), which is higher than the 45.5% from group 2 (10 out of 22 patients). In group 1, mean serum fT4 level (0.80 +/- 0.27 ng/dL at the baseline, 0.98 +/- 0.21 ng/dL after 3 months) and the TSH level (37.95 +/- 81.76 micro IU/mL at the baseline, 25.66 +/- 70.79 micro IU/mL after 3 months) changed significantly during this period (p < 0.05). In group 2, the mean serum fT4 level decreased (0.98 +/- 0.17 ng/dL at baseline, 0.92 +/- 0.28 ng/dL after 3 months, p < 0.05). In the iodine restriction group, the urinary iodine excretion values were higher in the recovered patients than in non-recovered patients (3.51 +/- 1.62 mg/L vs. 1.21 +/- 0.39 mg/ L, p=0.006) and the initial serum TSH values were lower in the recovered patients than in the non-recovered patients (14.28 +/- 12.63 micro IU/mL vs. 123.14 +/- 156.51 micro IU/mL, p=0.005). In conclusion, 78.3% of patients with hypothyroidism due to Hashimoto's thyroiditis regained an euthyroid state iodine restriction alone. Both a low initial serum TSH and a high initial urinary iodine concentration can be predictable factors for a recovery from hypothyroidism due to Hashimoto's thyroiditis after restricting their iodine intake.     

Serum tonicity, extracellular volume and clinical manifestations in symptomatic dialysis-associated hyperglycemia treated only with insulin

The absence of osmotic diuresis modifies the effects of hyperglycemia on body fluids in patients with advanced renal failure. To determine the relationship between clinical manifestations and abnormalities in tonicity and extracellular volume in such patients, we analyzed 43 episodes of severe dialysis-associated hyperglycemia (serum glucose exceeding 600 mg/dL) treated only with insulin. The main manifestations were dyspnea in 22 cases (pulmonary edema in 19), nausea and vomiting in 15, coma in 13 and seizures in 3, while 5 patients had no symptoms. Treatment with insulin resulted in a decrease in serum glucose value from 913 +/- 197 mg/dL to 170 +/- 78 mg/dL, an increase in serum sodium level from 125 +/- 5 to 136 +/- 5 mmol/L, and a fall in calculated serum tonicity value from 300 +/- 13 to 282 +/- 11 mmol/kg (all at p < 0.001). The ratio of the change in serum sodium level over change in serum glucose concentration was -1.50 +/- 0.22 mmol/L per 100 mg/dL. The percent increase in extracellular volume secondary to hyperglycemia developing from the prior euglycemic state and calculated from changes in serum sodium and chloride concentrations, was 10.9% +/- 4.6% (1.5% +/- 0.6% per 100 mg/dL increase in serum glucose level). All clinical manifestations dissipated after correction of hyperglycemia in 42 patients. One woman developed during treatment a fatal myocardial infarction. Dialysis patients with severe hyperglycemia may develop symptoms as a result of hypertonicity and extracellular expansion. Insulin alone may be sufficient treatment for these symptoms. The changes in serum tonicity and electrolytes during treatment are consistent with theoretical predictions.     

Comparison of Clinical and Imaging Characteristics and Outcomes between Provoked and Unprovoked Acute Pulmonary Embolism in Koreans

This study was performed to compare clinical and imaging parameters and prognosis of unprovoked pulmonary embolism (PE), provoked PE with reversible risk factors (provoked-rRF), and provoked PE with irreversible risk factors (provoked-iRF) in Koreans. Three hundred consecutive patients (mean age, 63.6 ± 15.0 yr; 42.8% male) diagnosed with acute PE were included. The patients were classified into 3 groups; unprovoked PE, provoked-rRF, and provoked-iRF; 43.7%, 14.7%, and 41.7%, respectively. We followed up the patients for 25.4 ± 33.7 months. Composite endpoint was all-cause mortality and recurrent PE. The provoked-iRF group had significantly higher all-cause mortality, mortality from PE and recurrent PE than the unprovoked and provoked-rRF groups (P < 0.001, P < 0.001, and P = 0.034, respectively). Prognostic factors of composite endpoint in the unprovoked group were high creatinine (> 1.2 mg/dL; P < 0.001; hazard ratio [HR], 4.735; 95% confidence interval [CI], 1.845-12.152), C-reactive protein (CRP; > 5 mg/L; P = 0.002; HR, 5.308; 95% CI, 1.824-15.447) and computed tomography (CT) obstruction index (P = 0.034; HR, 1.090; 95% CI, 1.006-1.181). In conclusion, provoked-iRF has a poorer prognosis than unprovoked PE and provoked-rRF. Renal insufficiency, high CRP, and CT obstruction index are poor prognostic factors in unprovoked PE.     

Relationships between myocardial injury, all-cause mortality, vitamin D, PTH, and biochemical bone turnover markers in older patients with hip fractures

This study examined the relationships between myocardial injury as indicated by serum cardiac troponin I (cTnI) elevation, 25 hydroxyvitamin D [25(OH)D], and PTH status and biochemical markers of bone metabolism in older patients with hip fracture (HF). In 238 consecutive patients (mean age 81.9 +/- 7.8 yr; 72% women) with low trauma HF, serum concentrations of cTnI, 25(OH)D, PTH, calcium, phosphorus, magnesium, osteocalcin, bone-specific alkaline phosphatase (BAP), and urine excretion of free deoxypyridinoline (DPD) and N-terminal cross-linked teleopeptide of type I collagen (NTx) were measured and clinical data were collected prospectively. Myocardial injury (cTnI >0.06 microg/L) presented in 29%, 25(OH)D deficiency (<50 nmol/L) in 81.6%, elevated PTH (>6.5 pmol/L) in 53%, and excessive bone resorption (increased DPD and/or NTx excretion) in 93.7%. Multivariate logistic regression showed that elevated serum PTH level is a major predictor of peri-operative myocardial injury (OR = 2.13; 95% CI 1.01-4.51; p = 0.049) and in-hospital all-cause mortality (OR = 18.5; 95% CI 2.0-72.3; p = 0.010), independent of age, sex, 25(OH)D status, and comorbidities. The degree of hyperparathyroidism was associated with the risk of cTnI elevation and the mortality rate. In cTnI positive patients, PTH levels correlated with cTnI concentrations (r = 0.28; p = 0.026) and urine DPD exretion (r = 0.37; p = 0.004). These results suggest for the first time that in older patients with HF, elevated PTH level is associated with peri-operative myocardial injury and in-hospital all-cause mortality, and that elevated PTH level contributes to both disturbed bone metabolism and poor outcomes.     

Mechanisms of hyperkalemia associated with hyporeninemic hypoaldosteronism in streptozotocin-induced diabetic rats.

This study was aimed at investigating the mechanisms of clinically important overt hyperkalemia in diabetes mellitus with underlying hyporeninemic hypoaldosteronism known as a classic model of the syndrome of hyporeninemic hypoaldosteronism (SHH). Rats (Sprague-Dawley, male) were streptozotocin-treated (60 mg/kg, ip) and used after 60 days. Rats with plasma glucose levels higher than 300 mg/dL (mean +/- SEM, 423 +/- 20 mg/dL, n = 8) were selected as the diabetic group. Age-matched normal rats served as control (mean plasma glucose, 88 +/- 2, mg/dL, n = 8). Serum potassium concentrations and osmolalities as well as serum creatinine levels were significantly higher in the diabetic than in the control group (5.07 +/- 0.09 vs. 4.68 +/- 0.11 mEq/L; 330 +/- 14 vs 290 +/- 3 mOsm/L; 0.40 +/- 0.03 vs 0.31 +/- 0.02 mg/dL, p < 0.05). Plasma renin activity (PRA) in the diabetic group was significantly lower than that in the control group (6.0 +/- 1.0 vs 12.1 +/- 1.1 ng Al/ml/h, p < 0.001). Plasma aldosterone concentration (PAC) was also significantly lower in the former than in the latter (368 +/- 30 vs 761 +/- 57 pg/ml, p < 0.001). Renomegaly, abnormal distal tubular cells with few organelles, and increased lipid droplets with pyknotic nucleus in zona glomerulosa of the adrenal glands were noted in the diabetic group. In conclusion, multifactorial causes including insulinopenia, hyperosmolality, elevated serum creatinine level and hypoaldosteronism with possible contribution of altered distal tubular response to aldosterone may have interacted to develop hyperkalemia in these diabetic rats.     

Interactions between magnesium and psychotropic drugs

Psychotropic drugs (antidepressants, antimanic drugs, antipsychotics, analgesic opioids, and others) are among the most frequently used medicines. Between these drugs and magnesium there are pharmacokinetic and pharmacodynamic interactions. Erythrocyte magnesium is decreased in patients with severe major depression (MD) vs normal subjects (44 +/- 2.7 mg/L in MD group vs 59.1 +/- 3.2 mg/L in control group, p < 0.01). Therapy with sertraline, 150 mg/day p.o. -21 days or with amitryptiline 3 x 25 mg/day p.o. 28 days increases significantly erythrocyte concentration of magnesium (56.9 +/- 5.22 mg/L after sertraline vs 44 +/- 2.7 mg/L before sertraline, p < 0.01). In patients with acute paranoid schizophrenia, erythrocyte magnesium concentration is decreased vs healthy subjects. Haloperidol, 8 mg/day, p.o. for 21 days or risperidone, 6 mg/day p.o. for 21 days have increased significantly erythrocyte magnesium concentration (46.21 +/- 3.1 mg/L before haloperidol and 54.6 +/- 2.7 mg/L after haloperidol, p < 0.05). Antimanic drugs (mood stabilizers) as carbamazepine, 600 mg/day, p.o., 4 weeks and sodium valproate, 900 mg/day p.o., 4 weeks, increased significantly magnesium in patients with bipolar disorder type I. Increased magnesium status positively correlated with enhancement of the clinical state. The existent data sustain the idea that an increase of erythrocyte magnesium is involved in the mechanism of action of some psychotropic drugs. Magnesium supply decreased the intensity of morphine-induced physical drug dependence. In heroin addicts, the plasma magnesium concentration is decreased.     

Correlation of serum HDL-cholesterol and LCAT levels with the fraction of ionized magnesium in children.

Correlation of serum lipids and apolipoprotein levels with serum total magnesium concentration and whole blood ionized magnesium level was determined in 47 children (14 female and 33 male; mean age, 8.7 +/- 4.2 years). Mean serum concentration of magnesium was 2.19 +/- 0.19 mg/dl, whole blood concentration of ionized magnesium 1.23 +/- 0.08 mg/dl, and fraction of ionized magnesium (ratio of whole blood ionized magnesium to serum total magnesium) 0.56 +/- 0.04. Neither serum total magnesium level nor whole blood ionized magnesium level had any correlation with serum albumin, lipid, and apolipoprotein levels. However, the fraction of ionized magnesium was significantly correlated with HDL-cholesterol (n = 46, r = 0.31, p = 0.0345), apolipoprotein A-1 (n = 41, r = 0.39, p = 0.0124), and lecithin-cholesterol acyltransferase (LCAT) (n = 20, r = 52, p = 0.0184). These results suggest that fraction of ionized magnesium is more closely linked to serum HDL-cholesterol and LCAT level than with the serum total magnesium level or whole blood ionized magnesium.     

A comparative study of serum lipid profile and gallstone disease

The diseased gallbladder is one of the commonest specimens submitted to the surgical pathology laboratory in North India. Obesity is associated with a linear increase in gallstone formation. It has been observed that the plasma lipoprotein profile of patients with gallstones differs markedly from that of healthy subjects. Serum lipid profile was done by enzyme kit method. All the gallstones received were categorized morphologically and examined biochemically. The age range of 200 cases was 13 to 77 years with a mean of43.75 +/- 13.39 years. There were 171 females (85.5%) and 29 males (14.5%) with male to female ratio of 1: 5.8. The stones containing both cholesterol and bile pigments were the most common (129 cases, 84.87%); while pure cholesterol stones were seen in 23 cases (11.50%) and pigment stones were infrequent (1 case, 0.65%). On lipidogram of patients in the study group, mean serum total cholesterol was 155.50 +/- 43.03 mg/dL, mean serum triglycerides was 100.49 +/- 45.23 mg/dL, mean HDL cholesterol was 46.71 +/- 15.20 mg/dL, mean LDL cholesterol was 87.94 +/- 36.85 mg/dL and mean VLDL cholesterol was 20.84 +/- 11.97 mg/dL. Serum total cholesterol values were significantly higher in patients older than 39 years as compared to patients < or =39 years (161.44 +/- 42.32 mg/dL vs. 145.79 +/- 32.96 mg/dL, p < 0.05). But the observed mean values in both of these subgroups were within the normal range i.e. <200 mg/dL. No significant difference was observed in the mean serum triglyceride values between male and female patients. The findings of this study did not indicate any role of serum lipid profile in the formation of gallstones. However the higher mean values of serum total cholesterol and serum triglycerides in patients older than 39 years of age may be explained by increasing age.     

Reduced cholesterol levels in African-American adults with sickle cell disease

In a recent study of boys and girls with sickle cell disease (SCD) in Nigeria, a common finding with this genetic hematologic disorder was a marked reduction in total cholesterol. Epidemiologic studies have identified a relation between low serum levels of total cholesterol (< 130 mg/dL) and increased mortality from all causes. We were interested in knowing if hypocholesterolemia was present in African-American adults with SCD. We therefore compared the plasma lipid profiles of the 16 men and 20 women with SCD who received care at the University of Texas Medical Branch at Galveston between 1996 and 2001 with those of 2,415 gender-matched African Americans who were seen at the same hospital but who did not have SCD. The age-adjusted mean total cholesterol concentrations of the SCD males and females were 147 +/- 42 mg/dL and 179 +/- 36 mg/dL, compared to male and female control values of 200 +/- 75 mg/dL and 216 +/- 61 mg/dL, respectively. These differences between SCD subjects and controls were statistically significant (p < 0.001). The LDL-cholesterol levels of the men and women with SCD (68 +/- 28 mg/dl and 95 +/- 33 mg/dl, respectively) were also significantly reduced relative to the controls (121 +/- 58 mg/dl and 128 +/- 54 mg/dl, respectively, p = 0.001). The triglyceride levels of the men with SCD were much reduced relative to the male controls (102 +/- 34 mg/dL versus 194 +/- 215 mg/dL, p = 0.02), but were not different between the SCD females and their control group. The HDL-cholesterol levels of the SCD subjects and the controls were not different. These results indicate that total cholesterol and LDL-cholesterol concentrations are significantly reduced in adult men and women with SCD in the United States, and should heighten interest in the implication that low levels of cholesterol might exacerbate the medical problems inherent in this genetic disease.     

The Relationship between Magnesium and Endothelial Function in End-Stage Renal Disease Patients on Hemodialysis

PurposeChronic kidney disease (CKD) patients tend to have higher serum magnesium values than healthy population due to their positive balance of magnesium in kidney. Recent studies found that magnesium level is positively correlated with endothelial function. Therefore, this study was conducted to define the relationship between magnesium level and endothelial dysfunction in end stage renal disease (ESRD) patients on hemodialysis (HD).ResultsIn the univariate analysis, higher magnesium levels were associated with better endothelium-dependent vasodilation (EDV) of the FMD in ESRD patients on HD (r=0.516, p=0.007). When the participants were divided into two groups according to the median magnesium level (3.47 mg/dL), there was a significant difference in EDV of FMD (less than 3.47 mg/dL, 2.8±1.7%; more than 3.47 mg/dL, 5.1±2.0%, p=0.004). In multivariate analysis, magnesium and albumin were identified as independent factors for FMD (β=1.794, p=0.030 for serum magnesium; β=3.642, p=0.012 for albumin).ConclusionThis study demonstrated that higher serum magnesium level may be associated with better endothelial function in ESRD patients on HD. In the future, a large, prospective study is needed to elucidate optimal range of serum magnesium levels in ESRD on HD patients.     

Pretransplant Neutropenia Is Associated with Poor-Risk Cytogenetic Features and Increased Infection-Related Mortality in Patients with Myelodysplastic Syndromes

A retrospective cohort analysis was performed to determine the impact of neutropenia on the outcome of hematopoietic cell transplantation (HSCT) in patients with myelodysplasia (MDS). Among 291 consecutive patients, 178 (61%) had absolute neutrophil counts (ANCs) <1500/μL and 113 (39%) had ANCs ≥1500/μL within 2 weeks before HSCT. Neutropenic patients more often had poor-risk karyotypes (34% versus 12%, P < .0001) and high-risk International Prognostic Scoring System scores (37% veresus 18%, P = .0006). After HSCT, the rate of infections caused by Gram-positive bacteria and invasive fungal infections was significantly increased among neutropenic patients (rate ratio [RR] 1.77, P = .02 and RR = 2.56, P = .03, respectively), whereas infections caused by Gram-negative bacteria were not affected (RR 1.33, P = .53). The hazards of nonrelapse mortality (NRM) (hazard ratio [HR] = 1.62 [1.1-2.4], P = .01), overall mortality (HR = 1.55 [1.1-2.1], P = 0.007), and infection-related mortality (HR = 2.22 [1.2-4.2], P = .01) were increased in neutropenic patients, whereas relapse, engraftment, and graft-versus-host-disease were not affected. After adjusting for cytogenetic risk and marrow myeloblast percentages, neutropenic patients remained at significant hazard for infection-related mortality (HR = 1.94 [1.0-3.8], P = .05), but not for overall mortality or NRM. We propose that intensified strategies to prevent infections should be implemented in MDS patients with preexisting neutropenia who undergo HSCT.     

Improvement of sleep apnea in patients with chronic renal failure who undergo nocturnal hemodialysis

BACKGROUND: Sleep apnea is common in patients with chronic renal failure and is not improved by either conventional hemodialysis or peritoneal dialysis. With nocturnal hemodialysis, patients undergo hemodialysis seven nights per week at home while sleeping. We hypothesized that nocturnal hemodialysis would correct sleep apnea in patients with chronic renal failure because of its greater effectiveness. METHODS: Fourteen patients who were undergoing conventional hemodialysis for four hours on each of three days per week underwent overnight polysomnography. The patients were then switched to nocturnal hemodialysis for eight hours during each of six or seven nights a week. They underwent polysomnography again 6 to 15 months later on one night when they were undergoing nocturnal hemodialysis and on another night when they were not. RESULTS: The mean (+/-SD) serum creatinine concentration was significantly lower during the period when the patients were undergoing nocturnal hemodialysis than during the period when they were undergoing conventional hemodialysis (3.9+/-1.1 vs. 12.8+/-3.2 mg per deciliter [342+/-101 vs. 1131+/-287 micromol per liter], P<0.001). The conversion from conventional hemodialysis to nocturnal hemodialysis was associated with a reduction in the frequency of apnea and hypopnea from 25+/-25 to 8+/-8 episodes per hour of sleep (P=0.03). This reduction occurred predominantly in seven patients with sleep apnea, in whom the frequency of episodes fell from 46+/-19 to 9+/-9 per hour (P= 0.006), accompanied by increases in the minimal oxygen saturation (from 89.2+/-1.8 to 94.1+/-1.6 percent, P=0.005), transcutaneous partial pressure of carbon dioxide (from 38.5+/-4.3 to 48.3+/-4.9 mm Hg, P=0.006), and serum bicarbonate concentration (from 23.2+/-1.8 to 27.8+/-0.8 mmol per liter, P<0.001). During the period when these seven patients were undergoing nocturnal hemodialysis, the apnea-hypopnea index measured on nights when they were not undergoing nocturnal hemodialysis was greater than that on nights when they were undergoing nocturnal hemodialysis, but it still remained lower than it had been during the period when they were undergoing conventional hemodialysis (P=0.05). CONCLUSIONS: Nocturnal hemodialysis corrects sleep apnea associated with chronic renal failure.     

High ratio of triglycerides to HDL-cholesterol predicts extensive coronary disease

An abnormal ratio of triglycerides to HDL-cholesterol (TG/HDL-c) indicates an atherogenic lipid profile and a risk for the development of coronary disease. OBJECTIVE: To investigate the association between lipid levels, specifically TG/HDL-c, and the extent of coronary disease. METHODS: High-risk patients (n=374) submitted for coronary angiography had their lipid variables measured and coronary disease extent scored by the Friesinger index. RESULTS: The subjects consisted of 220 males and 154 females, age 57.2+/-11.1 years, with total cholesterol of 210+/-50.3 mg/dL, triglycerides of 173.8+/-169.8 mg/dL, HDL-cholesterol (HDL-c) of 40.1+/-12.8 mg/dL, LDL-cholesterol (LDL-c) of 137.3+/-46.2 mg/dL, TG/HDL-c of 5.1+/-5.3, and a Friesinger index of 6.6+/-4.7. The relationship between the extent of coronary disease (dichotomized by a Friesenger index of 5 and lipid levels (normal vs. abnormal) was statistically significant for the following: triglycerides, odds ratio of 2.02 (1.31-3.1; p=0.0018); HDL-c, odds ratio of 2.21 (1.42-3.43; p=0.0005); and TG/HDL-c, odds ratio of 2.01(1.30-3.09; p=0.0018). However, the relationship was not significant between extent of coronary disease and total cholesterol [1.25 (0.82-1.91; p=0.33)] or LDL-c [1.47 (0.96-2.25; p=0.0842)]. The chi-square for linear trends for Friesinger >4 and lipid quartiles was statistically significant for triglycerides (p=0.0017), HDL-c (p=0.0001), and TG/HDL-c (p=0.0018), but not for total cholesterol (p=0.393) or LDL-c (p=0.0568). The multivariate analysis by logistic regression OR gave 1.3+/-0.79 (p= .0001) for TG/HDL-c, 0.779+/-0.074 (p= .0001) for HDL-c, and 1.234+/-0.097 (p=0.03) for LDL. Analysis of receiver operating characteristic curves showed that only TG/HDL-c and HDL-c were useful for detecting extensive coronary disease, with the former more strongly associated with disease. CONCLUSIONS: Although some lipid variables were associated with the extent of coronary disease, the ratio of triglycerides to HDL-cholesterol showed the strongest association with extent.     

Periodic limb movements in sleep and iron status in children

STUDY OBJECTIVES: To assess potential relationships between serum iron and ferritin levels and the severity of periodic limb movement in sleep (PLMS) in a pediatric population, and to evaluate the response to supplemental iron therapy. DESIGN: A prospective study of all consecutively diagnosed children with PLMS (periodic limb movement index [periodic limb movements per hour of total sleep time, [PLMI] > 5) who underwent overnight polysomnographic evaluation. In all patients, complete blood count and serum iron and ferritin levels were obtained. Patients with serum ferritin concentrations less than 50 microg/L were prescribed iron sulfate at 3 mg/kg of elemental iron per day for 3 months. At the end of treatment, serum iron and ferritin levels and sleep studies were repeated. SETTING: Comprehensive Sleep Medicine Center, Tulane University Health Sciences Center, and Kosair Children's Hospital Sleep Medicine and Apnea Center. PATIENTS: Twenty boys and 19 girls with PLMS with a mean age of 7.5 +/- 3.1 years. INTERVENTION: Iron therapy. RESULTS: Twenty-eight (71.8%) patients had ferritin levels less than 50 microg/L. There was no significant correlation between serum ferritin concentration and PLMS severity as indicated by the PLMI (r = -0.19). The PLMI in patients with serum ferritin levels less than 50 microg/L (29.9 +/- 15.5 PLM/h) was higher than in patients with serum ferritin levels greater than 50 microg/L (21.9 +/- 11.8 PLM/h); however, the difference did not achieve statistical significance (P = 0.09). In contrast, serum iron was significantly correlated with PLMI (r = -0.43, P < 0.01). Indeed, patients with serum iron concentrations less than 50 microg/dL had a higher PLMI compared to patients with serum iron concentrations greater than 50 microg/dL (42.8 +/- 18.3 PLM/h and 23.1 +/- 10.1 PLM/h, respectively; P = 0.02). Twenty-five out of the 28 PLMS patients with serum ferritin levels less than 50 microg/L received treatment with iron sulfate, and 19 (76%) responded favorably. Among the responders to iron therapy, PLMI decreased from 27.6 +/- 14.9 PLM per hour to 12.6 +/- 5.3 PLM per hour after 3 months of iron supplements (P < 0.001) and coincided with increases in serum ferritin levels (pre: 40.8 +/- 27.4 microg/L vs post: 74.1 +/- 13.0 microg/L; P < 0.001). CONCLUSIONS: In children, the presence of PLMS is frequently associated with low serum iron and a tendency toward low serum ferritin levels. In addition, iron therapy is associated with clinical improvement in most of these patients.