Computer assisted sound analysis of arteriovenous fistula in hemodialysis patients.

The purpose of this study was to reveal the unique sound characteristics of the bruit produced by arteriovenous fistulae (AVF), using a computerized method. An electronic stethoscope (20 Hz to 20 000 Hz sensitivity) was used, connected to a portable laptop computer. Forty prevalent hemodialysis patients participated in the study. All measurements were made with patients resting in supine position, prior to the initiation of mid-week dialysis session. Standard color Doppler technique was used to estimate blood flow. Clinical examination revealed the surface where the perceived bruit was more intense, and the recording took place at a sample rate of 22 000 Hz in WAV lossless format. Fast Fourier Transform (FFT) mathematical algorithm, was used for the sound analysis. This algorithm is particularly useful in revealing the periodicity of sound data as well as in mapping its frequency behavior and its strength. Produced frequencies were divided into 40 frequency intervals, 250 Hz apart, so that the results would be easier to plot and comprehend. The mean age of the patients was 63.5 ± 14 years; the median time on dialysis was 39.6 months (mean 1 month, max. 200 months). The mean blood flow was 857.7 ± 448.3 ml/min. The mean sound frequency was approximately 5 500 Hz ± 4 000 Hz and the median, which is also expressing the major peak of sound data, was 750 Hz, varying from 250 Hz to 10 000 Hz. A possible limitation of the study is the relatively small number of participants.

Association of iron depletion with menstruation and dietary intake indices in pubertal girls: the healthy growth study.

The aim of the present study was to investigate the associations of iron depletion (ID) with menstrual blood losses, lifestyle, and dietary habits, in pubertal girls. The study sample comprised 1222 girls aged 9-13 years old. Biochemical, anthropometrical, dietary, clinical, and physical activity data were collected. Out of 274 adolescent girls with menses, 33.5% were found to be iron depleted (defined as serum ferritin < 12 µg/L) compared to 15.9% out of 948 girls without menses. Iron-depleted girls without menses were found to have lower consumption of poultry (P = 0.017) and higher consumption of fruits (P = 0.044) and fast food (P = 0.041) compared to their peers having normal iron status. Multivariate logistic regression analysis showed that girls with menses were 2.57 (95% CI: 1.37, 4.81) times more likely of being iron depleted compared to girls with no menses. Iron depletion was found to be associated with high calcium intake, high consumption of fast foods, and low consumption of poultry and fruits. Menses was the only factor that was found to significantly increase the likelihood of ID in these girls. More future research is probably needed in order to better understand the role of diet and menses in iron depletion.

Phosphate binders in chronic kidney disease. When should we start, what should we prescribe?

It has been more than 2000 years since Hippocrates described renal disease and observed its progressive nature. Decreased survival and deteriorated health status of these patients' being is attributed to cardiovascular disease. There is increasing interest regarding the impact of non-traditional risk factors, including hyperphosphatemia, elevated calcium-phosphate (CaxPO(4)) product, elevated parathyroid hormone levels and extensive use of calcium-containing phosphate binders on vascular calcification. There is a mounting body of evidence implying that a holistic and methodic approach should clearly suggest starting the battle against vascular calcification early in the course of chronic kidney disease. Type of phosphate binder used should be carefully selected, especially in the presence of vascular calcification.

Pharmacological management of hypertensive emergencies and urgencies: focus on newer agents.

INTRODUCTION: Hypertensive crises are categorized as hypertensive emergencies and urgencies depending on the presence of acute target-organ damage; the former are potentially life-threatening medical conditions, requiring urgent treatment under close monitoring. Although several short-acting intravenous antihypertensive agents are approved for this purpose, until recently little evidence from proper trials on the relative merits of different therapies was available. AREAS COVERED: This article discusses in brief the pathophysiology, epidemiology and diagnostic approach of hypertensive crises and provides an extensive overview of established and emerging pharmacological agents for the treatment of patients with hypertensive emergencies and urgencies. EXPERT OPINION: Agents such as sodium nitroprusside, nitroglycerin and hydralazine have been used for many years as first-line options for patients with hypertensive emergencies, although their potential adverse effects and difficulties in use were well known. With time, equally potent and less toxic alternatives, including nicardipine, fenoldopam, labetalol and esmolol are increasingly used worldwide. Recently, clevidipine, a third-generation dihydropyridine calcium-channel blocker with unique pharmacodynamic and pharmacokinetic properties was added to our therapeutic armamentarium and was shown in clinical trials to reduce mortality when compared with nitroprusside. In view of such evidence, a change in pharmacological treatment practices for hypertensive crises toward newer and safer agents is warranted.

A study of the association of higher parathormone levels with health-related quality of life in hemodialysis patients.

Secondary hyperparathyroidism (SHPT) is associated with poor outcome including mortality, hospitalization, as well as greater healthcare resource utilization and costs in chronic kidney disease (CKD). We hypothesized that SHPT is also associated with poor self reported health-related quality of life (HRQOL) in prevalent hemodialysis (HD) patients. We conducted a case-control study in patients with CKD receiving longterm HD treatment, in six dialysis clinics in Greece. HRQOL was estimated with the KDQOL-SFTM questionnaire, version 1.3, which includes 43 kidney disease targeted items, and 36 items that provide a generic core and an overall health rating item, with a higher score reflecting a more favorable health state. A total of 156 completed the questionnaire, 50 with high parathormone levels (i.e., PTH > 300 pg/ml and or under vitamin D receptor activators, mean: 329 ± 160.9 pg/ml) and 106 with low parathormone levels (PTH < 300 pg/ml, mean: 132.4 ± 69.0 pg/ml) in a 2 : 1 randomization assignment. Patients with high and with low PTH were 62.1 ± 14.9 and 65.9 ± 14.2 y old and the median dialysis vintage time was 31 and 37 months, respectively. There were no significant differences regarding the presence of comorbidities between groups. Patients with high PTH, compared to patients with low PTH, had lower pain component summary (57.6 ± 33.5 vs. 69.2 ± 28.9; p = 0.041) and physical component summary (41.0 ± 23.8 vs. 50.0 ± 20.8; p = 0.031). Both pain component summary and physical component summary differences remained significant after adjustment for age, gender and vintage (p = 0.036 and p = 0.029, respectively). Low PTH patients scored better in 18 out of 23 subscales. In HD patients, SHPT appears to be associated with worse pain component summary score (p = 0.036) and physical component summary score (p = 0.029). Additional studies are needed to verify these associations and to examine whether correction of SHPT can improve HRQOL.

Hemodialysis reduces augmentation index but not aortic or brachial pulse wave velocity in dialysis-requiring patients.

BACKGROUND/AIMS: Arterial stiffening characterizes the vasculature of end-stage renal disease (ESRD) patients and is a strong predictor of their cardiovascular morbidity and mortality. Previous studies evaluating the effect of hemodialysis on large artery elasticity gave contradictory results. This study aimed to investigate the impact of hemodialysis on arterial stiffness and wave reflections on chronic hemodialysis patients. METHODS: A total of 51 stable ESRD patients on maintenance hemodialysis were evaluated before and after the first and second dialysis session of the week. Arterial stiffness was assessed by measuring aortic and brachial pulse wave velocity (PWV). Central arterial pressure waveform parameters were estimated by radial artery applanation tonometry. Heart rate-adjusted augmentation index [AIx(75)] was used as measure of wave reflections. RESULTS: During both dialysis sessions systolic blood pressure (SBP) and pulse pressure (PP) at brachial artery and central aorta were reduced. AIx(75) was decreased in first and second weekly dialysis session (27.5 ± 1.2 vs. 21.0 ± 1.5, p < 0.001 and 24.7 ± 1.2 vs. 20.5 ± 1.5, p < 0.001, respectively). In contrast, aortic and brachial PWV remained unchanged during both dialysis sessions. Changes in AIx(75) during hemodialysis were associated with changes in central aortic SBP, PP and ejection duration. CONCLUSIONS: This study shows that hemodialysis does not acutely affect arterial stiffness, but reduces wave reflections from periphery. This dissociation between effects of hemodialysis on PWV and AIx(75) may reflect differential impact on large and small branches of the arterial tree.

Haemostatic profile of healthy premature small for gestational age neonates.

BACKGROUND: The pathogenetic profile of premature Small for Gestational Age (SGA) neonates is strongly related to their haemostatic equilibrium, which is inadequately understood. OBJECTIVE: To evaluate coagulation and fibrinolysis in premature SGA neonates before intervening with Vitamin K administration. STUDY DESIGN: We performed a comparison of coagulation, natural inhibitors and fibrinolysis between SGA and Appropriate for Gestational Age (AGA) infants born prematurely [gestational age (G.A.) <37 weeks]. Study population consisted of 139 preterm newborns, 68 of whom were SGA (25 males and 43 females), while 71 were AGA (37 males and 34 females) that consisted the control group. Blood samples were obtained within 30 minutes following birth and before the administration of vitamin K. Investigation included: PT, INR, APTT, fibrinogen, coagulation factors II, V, VII, VIII, IX, X, XI, XII, von Willebrand factor, protein C and free protein S, antithrombin (AT), APCR, tPA and PAI-1. The independent t-test and the Mann-Whitney U test were used to compare the differences between the values of haemostatic parameters. RESULTS: Premature SGA infants presented significantly lower levels of fibrinogen (p<0.029) and higher levels of VIIIc factor, APCR, tPA and PAI-1 (p<0.041, 0.017, 0.021 and 0.019 respectively). The two groups had similar demographic characteristics (except from birth weight), without significant differences in the values of other haemostatic parameters. CONCLUSIONS: Despite the statistically significant differentiation in the levels of fibrinogen, VIIIc factor, APCR, tPA and PAI-1, the rest of haemostatic parameters have similar values between SGA and AGA preterms.

Risk factors for childhood obesity in a Greek paediatric population.

OBJECTIVE: Obesity in children is a serious public health issue in Greece. The purpose of the current study was to identify risk factors such as birth weight, breast-feeding, dietary patterns, family history of obesity and sedentary behaviours that are possibly associated with paediatric obesity. DESIGN: Two hundred and five overweight and obese children (OW/OB; group 1) aged 7-15 years from eight primary and secondary schools and a control group (group 2) of normal-weight children were matched for age and sex. Overweight and obesity were calculated based on the International Obesity Taskforce criteria. Lifestyle parameters as well as anthropometric data were collected in all children. Conditional logistic regression analysis was used to identify risk factors for obesity. RESULTS: Breast-feeding (> or =3 months) and leisure-time physical activity proved to be protector factors against obesity (OR = 0.21, 95 % CI 0.11, 0.79, P < 0.001 and OR = 0.87, 95 % CI 0.85, 0.89, P < 0.001 respectively). On the other hand, family history of obesity (OR = 3.79, 95 % CI 2.61, 4.18, P < 0.001), sugar-sweetened beverage consumption (OR = 1.77, 95 % CI 1.03, 2.76, P < 0.001) and watching television (OR = 1.99, 95 % CI 1.54, 2.76, P = 0.04) were found to be positively associated with a higher obesity risk. CONCLUSIONS: The current findings support the literature according to which duration of breast-feeding (<3 months), a family history of obesity, watching television, sedentary lifestyle and consumption of sugar-sweetened beverages are important risk factors for childhood obesity. More studies are needed to elucidate the relationship of paediatric obesity and possible predictor factors in order to avoid health consequences in these children later on in life.

A rare retroperitoneal schwannoma in a patient with neurofibromatosis Type 2.

Neurofibromatosis Type 2 (NF2) is a dominantly inherited tumour-prone disorder, characterized by the development of multiple schwannomas, meningiomas and ependymomas. Its prevalence is around 1:60 000. Vestibular schwannoma (VS) is the hallmark of NF2. Retroperitoneal schwannomas are expected to occur in only 3% of cases. We present the case of a large retroperitoneal schwannoma in a patient with NF2. A well-circumscribed heterogenic mass (9.5 × 4 × 4 cm) behind and under the left kidney and extending into the left retroperitoneal space was revealed during a lumbar and retroperitoneal space magnetic resonance imaging (MRI). Brain, orbits, cervical, thoracic and lumbar MRI revealed bilateral VS, multiple meningiomas as well as multiple schwannomas and ependymomas in the cervical, thoracic and lumbar spine. The retroperitoneal mass represents a schwannoma probably derived from an intercostal nerve. The patient underwent neurosurgical excision of the VS, and 3 months later, the patient's condition remained stable.

Possible Health Implications and Low Vitamin D Status during Childhood and Adolescence: An Updated Mini Review.

Vitamin D deficiency is common in the developing countries and exists in both childhood and adult life. The great importance of Vitamin D is the moderation of calcium (Ca) and phosphorus (P) homeostasis as well as the absorption of Ca. While insufficiency of vitamin D is a significant contributing factor to risk of rickets in childhood, it is possible that a more marginal deficiency of vitamin D during life span contribute to osteoporosis as well as potentially to the development and various other chronic diseases such as cardiovascular disease, cancer and diabetes. This paper reviews the metabolism, epidemiology, and treatment of vitamin D and calcium insufficiency as well as its relation to various diseases during childhood and adolescence.

Haemostatic profile of full-term, healthy, small for gestational age neonates.

BACKGROUND: Small for Gestational Age (SGA) neonates often appear with haemostatic alterations, principally due to hepatic dysfunction that results from chronic intrauterine hypoxia. Polycythaemia and thrombocytopenia are common findings in this neonatal population. STUDY DESIGN: We performed a comparison of coagulation, natural inhibitors and fibrinolysis between SGA and Appropriate for Gestational Age (AGA) infants born full term [gestational age (G.A.) >37 weeks]. Study population consisted of 188 healthy newborns, 90 of whom were SGA (62 females and 28 males), while the rest were the control group (44 females and 54 males). Blood samples were obtained within 30 minutes following birth and before the administration of vitamin K. Investigation included: PT, INR, APTT, fibrinogen, coagulation factors II, V, VII, VIII, IX, X, XI, XII, vWillebrand factor, protein C and free protein S, antithrombin (AT), APCR, tPA and PAI-1. The independent t-test was used to compare the differences between the values of haemostatic parameters. RESULTS: Statistical analysis revealed a significant prolongation in PT, INR, elevated levels of tPA (p<0.015, 0.01 and 0.002 respectively) and a decrease in the values of XII and free protein S (p<0.045 and 0.007 respectively) in SGA full term neonates. The two groups had similar demographic characteristics (except birth weight), without significant differences in the values of other haemostatic parameters. CONCLUSIONS: Despite of statistically significant differences in PT, INR, values of tPA, XII and free protein S, levels of haemostatic factors range within laboratory references for healthy full term newborns. These findings were not accompanied with clinical manifestations of altered haemostasis.

Is there any association between high-density lipoprotein, insulin resistance and non-alcoholic fatty liver disease in obese children?

Non-alcoholic fatty liver disease (NAFLD) is estimated to occur in about 50% of obese children. The purpose of this study is to examine the association of anthropometric, biochemical and liver indexes in obese children with and without NAFLD and its relation with insulin resistance (IR). Forty-three obese children participated in the study. NAFLD was diagnosed by ultrasonography. Liver indices (SGOT, SGPT), lipid profile, glucose and insulin levels were performed in all patients. IR was measured by means of the homeostasis model assessment and oral glucose insulin sensitivity. Among the 43 obese patients, 18/43 (41.8%) had NAFLD based on ultrasonography. Fifty percent of them had mild steatosis and 50% had moderate/severe steatosis. In logistic regression analysis of factors associated with NAFLD, homeostasis model assessment IR (ExpB, 1.607; 95% confidence interval, 1.058-2.440; P <0.02) and high-density lipoprotein (0.952; 95% confidence interval, 0.814-1.075; P <0.03) were the most significant. IR, as has already been proved, is associated with NAFLD. Furthermore, high-density lipoprotein levels seem to play an additional role in predicting NAFLD in obese children.

Are saturated fatty acids and insulin resistance associated with fatty liver in obese children?

BACKGROUND: Fatty liver (FL) is a common cause of liver disease in children. Obesity and insulin resistance (IR) play an important role in pathogenesis of FL. Diet has been reported to affect IR and possibly FL. The purpose of this study was to investigate certain parameters (anthropometric, biochemical, dietary intake) of obese Greek children with and without FL. METHODS: Forty-three obese children aged 9-14 (25 boys/18 girls) participated in the study. FL was diagnosed by ultrasonography (US). Liver indexes (ALT, AST, gamma-GT) were measured in all children. A 3-day dietary was recorded for all subjects. None of the subjects were positive for viral hepatitis or had a history of consuming alcohol. RESULTS: Eighteen out of 43 subjects (41.8%) had FL based on US. Intakes of carbohydrates and simple refined carbohydrates were significantly higher in subjects with FL compared to children without FL, while saturated fatty acids (SFA) were proportionally increased to the degree of hepatic steatosis. In multiple regression analysis of factors associated with FL, only HOMA-IR [Beta: 0.160, 95%CI (0.122-1.340), P<0.001] and SFA [Beta: 0.455, 95%CI (0.129-2.129), P<0.001] were the most significant one. CONCLUSIONS: Our results suggest that high intake of carbohydrates and simple refined carbohydrates as well as low intake of fiber may be correlated with the pathogenesis of FL. Moreover, IR and high intake of SFA are independently associated with FL in obese children.

Slow intravenous iron administration does not aggravate oxidative stress and inflammatory biomarkers during hemodialysis: a comparative study between iron sucrose and iron dextran.

BACKGROUND/AIMS: Fast intravenous (i.v.) iron administration during hemodialysis (HD) is associated with the augmentation of oxidative stress and the increase in inflammatory biomarkers, which are also induced by the hemodialysis procedure itself. The aim of this study was to investigate if slow i.v. iron administration would aggravate the status of oxidative stress and inflammatory biomarkers during a hemodialysis session. METHODS: Twenty dialysis patients 30-92 years of age that were iron replete and had values for hemoglobin, transferrin saturation and serum ferritin among recommended goals were evaluated in three separate hemodialysis sessions. In the first session patients did not receive any iron treatment, whereas during the second and the third session patients received slow (60 min) i.v. infusions of 100 mg of iron sucrose and 100 mg of iron dextran, respectively. Blood samples were drawn before the hemodialysis session, 15 min after the end of iron administration and at the end of the hemodialysis session in all occasions, for the measurement of markers of oxidant stress (oxidized LDL and ischemia-modified albumin) and inflammation (high-sensitivity C-reactive protein, interleukin-6 and tumor necrosis factor-alpha). RESULTS: Oxidized LDL was not significantly altered during hemodialysis and this pattern was similar between the three occasions studied. In contrast, ischemia-modified albumin was significantly increased and this effect was also not different between the net hemodialysis and the occasions of iron administration. High-sensitivity CRP, IL-6 and TNF-alpha were all significantly elevated during hemodialysis and again both types of iron administration did not produce significant changes in this pattern. CONCLUSION: We did not find an increase in the markers of oxidation/inflammation studied, after slow i.v. iron administration during hemodialysis session.