液体控制对动脉导管未闭早产儿血流动力学的影响

目的探讨液体控制对动脉导管未闭早产儿血流动力学的影响。方法选择24周≤孕周32周并为显著性动脉导管未闭患儿21例;记录液体控制前和E1液体控制24 h E2后血流动力学和超声心动图变量。结果患儿未行液体控制时E1液体摄入量为(144.8±14.9)m L/(kg·d),液体控制后总液体摄入量减至(108.1±10.6)m L/(kg·d),E1和已行液体控制时总液体摄入量差异性显著(P=0.015);E2时尿量明显低于E1时,差异有统计学意义(P=0.007);SVC流速E1时中位值为113.7 m L/(kg·min),E2时中位值为63.3 m L/(kg·min),E2时SVC流速显著性降低(P=0.003);患儿SMA在E1时平均血流速度为(0.25±0.03)m/s,明显高于E2时(0.14±0.04)m/s,且差异性显著具有统计学意义(P=0.011)。结论液体控制并未对早产儿肺循环或体循环血流动力学产生有益的影响。     

Self‐reported quantity of normal maximal voided volume in healthy young

Bladder capacity is an important factor in the diagnosis and treatment of individuals with voiding dysfunction. In contrast, self‐reported quantity of normal maximal voided volume in healthy young is few. The purpose of this study was to define the quantity of normal maximal voided volume in healthy young. This prospective study was carried out in 72 students aged 17–24 years who did not have clinical voiding dysfunction undergoing nursing education in a University in Sakarya, Turkey. The study was conducted in December 2011. Healthy young were recruited to determine the quantity of the normal maximal voided volume. The maximal voided volume was determined in all subjects using a frequency volume chart with a voiding observation. In our study, the normal maximal voided volume (mL) for females was 413·3 ± 167.9 and the normal maximal voided volume (mL) for male was 589·2 ± 108·5. These formulas may be useful for the diagnosis of abnormal bladder capacity and the evaluation of voiding dysfunction in young. This research may be the source for studies that could include climate, cultures and different age groups.     

Endocrine and renal response to water loading and water restriction in normal man

1. Nine normal subjects (eight male, one female) on a fixed daily intake of 150 mmol of sodium and 80 mmol of potassium, were randomized to receive either 3 days of 1.0 litre total water intake/24 h (food + fluid) or 4 days of 6.8 litres total water intake/24 h, and were then crossed over after a 3 day control period (2.7 litres water/24 h). 2. During water restriction, urine volume fell from 1.94 litres/24 h to less than 1 litre/24 h by the first day and was 0.77 litre/24 h on the final day. Plasma atrial natriuretic peptide levels were unchanged from baseline despite a large increase in plasma vasopressin and plasma and urine osmolality. Urinary sodium was unaltered throughout, while urinary potassium was increased on the final 2 days of water restriction. 3. During water loading, urine volume increased from 1.85 litres/24 h to 5.44 litres/24 h on the first day and remained at approximately 6 litres/24 h for the final 3 days. Plasma atrial natriuretic peptide showed no change. Plasma vasopressin and plasma and urine osmolality were reduced. Urinary sodium and potassium output were unchanged from baseline. 4. These results suggest that changes in plasma atrial natriuretic peptide are unlikely to be involved in the normal homoeostatic response to changes in water balance in man.     

Inadequate fluid intake in long term care residents: prevalence and determinants

Dehydration is estimated to be present in half of long term care residents, as many do not consume the recommended levels of fluid intake. This study aims to describe fluid intake in long term care residents and identify the factors associated with fluid intake. Data were collected from 622 long term care residents, with a mean age of 86.8?±?7.8. Total fluid intake was estimated over three non-consecutive days. Potential resident and unit-level variables risk factors for low fluid intake were collected, such as dementia status, activities of daily living, and eating challenges. Average daily fluid intake ranged from 311–2390?mL (1104.1?±?379.3). Hierarchical regression analysis revealed that fluid intake was negatively associated with increased age, cognitive impairment, eating challenges and increased dining room staffing. Being male and requiring more physical assistance were positively associated with intake. Variables identified to predict intake could help inform strategies and targeted interventions to improve fluid intake.     

Age-related changes in male forearm skin-to-fat tissue dielectric constant at 300 MHz

Prior research suggests that tissue dielectric constant (TDC) values are useful to assess localized skin water in females for early diagnosing breast cancer treatment-related lymphoedema and TDC values in young adults have shown gender differences. However, no TDC data are available for older males nor have ageing effects been studied despite known shifts in water state and other skin age-related changes. Thus our goals were to (i) characterize TDC values at various skin depths in young and older males, (ii) determine the dependence of these values on body composition parameters and (iii) establish inter-arm TDC ratios for use as normal male reference values. TDC measurements were made to depths of 0·5, 1·5, 2·5 and 5·0 mm bilaterally on volar forearm skin in 60 males in three groups of 20 that had mean ages ± SD of 24·0 ± 0·9, 40·0 ± 12·9 and 71·0 ± 8·0 years. Total body fat and water percentages were determined via bioimpedance at 50 KHz. Results showed that (i) for all age groups TDC values decreased with increasing depth, (ii) TDC values were not statistically different among age groups except at a depth of 0·5 mm, (iii) TDC values were highly negatively correlated with total body fat and (iv) inter-arm ratios varied little among age groups and depths. It is concluded that (i) age-related larger TDC values at only the shallowest depth is consistent with skin water shifting state from bound to more mobile in the oldest group and (ii) inter-arm ratios at any depth provide a basis to test for unilateral oedema.     

Effect of pre-donation fluid intake on fluid shift from interstitial to intravascular compartment in blood donors

Background

Fluid shifts from interstitial to intravascular space during blood donation helps in compensating the lost blood volume. We aimed to determine the volume of fluid shift following donation in donors with and without pre-donation fluid intake.

Fluid homoeostasis during prolonged low-intensity walking on consecutive days

1. The effect on fluid homoeostasis of walking 37 km on each of 4 consecutive relatively cool days was studied in six male subjects. The daily exercise intensity was consistent and was equivalent to 17(1)% [mean (SE)] of maximum oxygen uptake for these subjects. 2. The diet during the study consisted of a mainly carbohydrate breakfast, consumed immediately before each day's exercise, and unrestricted access to a normal mixed diet after completion of each day's exercise. Water was allowed ad libitum during the walk. Food and fluid intake were recorded. 3. Body weight remained constant over the 4-day walk. The difference between total daily fluid intake and the corresponding 24 h urine output was 1684 (250) ml, 1621 (522) ml, 1107 (252) ml and 1406 (208) ml, respectively, on each of the 4 exercise days. 4. There was a calculated increase of 21.3(6.6)% in plasma volume over the 4-day walk; the largest daily change [11.3(2.9)%] occurred during the walk on day 1. The increase in plasma volume was maintained for at least 4 days after completion of the walk. 5. From day 2, serum sodium concentration tended to increase during the exercise period and fell to the pre-exercise concentration during the overnight rest periods. The concentration of the other measured serum constituents remained relatively constant, and serum osmolality did not alter over the study period.     

Low-dose theophylline increases urine output in diuretic-dependent critically ill children

Objective: Determine the effect of low-dose theophylline on urine output and the urinary adenosine: cAMP (cyclic adenosine monophosphate) excretion ratio (a measure of phosphodiesterase inhibition) in diuretic-dependent critically ill children. Design: Observational clinical case series and animal laboratory experiment. Setting: A university pediatric intensive care unit and a pharmacology research laboratory. Patients: 10 consecutive oliguric patients treated with theophylline for diuresis. Interventions: Urine output, fluid intake, diuretic dosages, and number of pressors (including dopamine) were monitored over the 24-h period prior to and the 24-h period immediately after theophylline was started. Hourly collections of urine were obtained at baseline and 1 and 3 h after theophylline was started and urinary excretion rates of adenosine and cAMP were measured and calculated. Measurements and results: Mean theophylline level in the children was 5.0 μg/ml. Urine output increased from 1.58 ± 0.46 to 3.75 ± 0.77 ml/kg per h (p = 0.008, paired t-test) after theophylline administration. There was no significant change in fluid intake, vasoactive agents, or dosages of other diuretics during the study periods. Intrarenal infusion of the IC50 concentration of isobutylmethylxanthine for phosphodiesterase activity resulted in a reduction of the adenosine: cAMP urinary excretion ratio in rats (p < 0.05). Low-dose theophylline had no effect on the adenosine: cAMP urinary excretion ratio in children. Concurrent therapy with dopamine was associated with an enhanced diuretic effect of theophylline (with dopamine, 1.30 ± 0.30 to 5.07 ± 0.77 ml/kg per h vs without dopamine, 1.77 ± 0.76 to 2.86 ± 1.08 ml/kg per h; p = 0.03, two-way ANOVA). There was no interaction between dopamine and low-dose theophylline on the urinary adenosine: cAMP excretion ratio (p = 0.56, two-way ANOVA). Conclusions: Theophylline increased urine output in diuretic-dependent critically ill children and the diuretic effect may have been potentiated by concurrent use of dopamine. Adenosine receptor antagonism may be a more likely mechanism for the diuretic effect of theophylline than phosphodiesterase inhibition. Received: 14 October 1997 Accepted: 9 July 1998     

The effects of a low level of dietary cadmium on blood pressure, '24Na, '42K, andwater retention in growing rats.

The effects of 5 pg Cd per millilter of drinking water on body weight gain, food intake, systolic blood pressure, '24Na, '42K; and water retention and freference for NaCl solution in male and female rats were studied. After 205 days, Cd had no significant effect on weight gain, food intake, water intake, or feed efficiency. The'24Na retention of the Cd-fed male and female rats was greater at 161 days than in the control animals and was significantly greater (P less than 0.05) in the Cd-treated females than in the control females at 294 days. In vivo retention of '42K was significantly greater in the Cd-treated males than in the control males at 189 days, butthe oppisite was true of the Cd-treated females in comparison with female control animals. There were no significant differences between treatments in '42K retention after 330 days. No significant differences were found between treatments in systolic blood pressure. Water retention was significantly greater in the Cd-treated males and females than in the control animals after 320 days. Preference for 0.20 M NaCl was significantly greater in the Cd-fed males than in the control males at 277 days.Possible mechanisms which might explain the sodium retention in thhe Cd-fed rat are discussed.     

The efficacy and toxicity of two dosing-regimens of amikacin in neonates with sepsis

What is known and objective: Neonatal sepsis is one of the most common reasons for admission to neonatal units in developing countries. Aminoglycosides widely used in its treatment are usually administered two or three times a day. Less frequent doing may be more convenient and as effective. We aim to compare the efficacy and safety (nephrotoxicity) of once daily vs. twice daily dosing of amikacin in neonates with suspected or proven sepsis and report on the drug’s pharmacokinetics in these subjects. Methods: Thirty neonates of gestational age ≥36 weeks and body weight ≥2500 g with suspected or proven sepsis were randomized to receive amikacin either at a dose of 15 mg/kg once per day; group I (n = 15), or a dose of 7·5 mg/kg twice per day, group II (n = 15). All neonates received classical treatment of sepsis including antibiotics, hemodynamic support, inotropic support based on blood pressure levels and size of the heart in chest X‐ray, if needed. Amikacin was infused over 1 h. Peak and trough serum samples for amikacin were measured for all infants at steady state. Nephrotoxicity was assessed by serum creatinine and urinary N‐acetyl β‐d ‐glucosaminidase before and 7 days after therapy. Clinical efficacy was compared using both observation of clinical status and normalization of laboratory tests. Results: All the patients in group I had achieved a trough level <10 μg/mL and two patients had trough concentration >10 μg/mL in group II. No significant difference between group I and group II in either baseline or day 7 serum creatinine was demonstrated (P > 0·05). No significant difference was found between the two groups in clinical efficacy or renal toxicity. The calculated pharmacokinetic parameters were in group I and II, respectively: clearance =63·8 ± 15·9 mL/kg/h and 73·5 ± 18·1 mL/kg/h; volume of distribution =0·54 ± 0·09 L/kg and 0·61 ± 0·13 L/kg, half‐life =6·1 ± 1·0 h and 5·95 ± 1·1 h. What is new and conclusion: As expected, amikacin given once every 24 h to septic neonates of ≥36 weeks of gestation achieved higher peak levels and lower trough concentrations than the twice daily regimen. Treatment with once daily regimen did not lead to more nephrotoxicity than with a twice‐daily regimen, and showed comparable efficacy.     

Determination of glycyrrhetic acid in human plasma by HPLC-MS method and investigation of its pharmacokinetics

Objective: To develop a high performance liquid chromatography mass spectrometry (HPLC‐MS) method for the determination of the glycyrrhetic acid (GA) in human plasma and for the investigation of its pharmacokinetics after the oral administration of 150 mg diammonium glycyrrhizinate test and reference capsule formulations. Methods: The GA in plasma was extracted with ethyl acetate, separated on a C₁₈ column with a mobile phase of methanol (5 mmol/L ammonium acetate)–water (85 : 15, V/V) and analysed using a MS detector. Ursolic acid (UA) was used as internal standard. The target ions were m/z 469·5 for GA and m/z 455·6 for UA, the fragment voltages were 200 V and 100 V for GA and UA respectively. Results: The calibration curve was linear over the range of 0·5–200 ng/mL (r = 0·9974). The limit of quantification for GA in plasma was 0·5 ng/mL, the recovery was 76·0–80·0%, and the inter‐ and intra‐day relative standard deviations (RSD) were <12%. The pharmacokinetic parameters of GA after a single dose of 150 mg diammonium glycyrrhizinate test and reference were as follows: the half life (t_1/2) 9·65 ± 3·54 h and 9·46 ± 2·85 h, the time to peak concentration (T_max) 10·95 ± 1·32 h and 11·00 ± 1·30 h, the peak concentration (C_max) 95·57 ± 43·06 ng/mL and 103·89 ± 49·24 ng/mL; the area under time‐concentration curve (AUC_0–48 and AUC_0–∞) 1281·84 ± 527·11 ng·h/mL and 1367·74 ± 563·27 ng·h/mL, 1314·32 ± 566·40 ng·h/mL and 1396·97 ± 630·06 ng·h/mL. The relative bioavailability of diammonium glycyrrhizinate capsule was 98·88 ± 12·98%. Conclusion: The assay was sensitive, accurate and convenient, and can be used for the determination of GA in human plasma. Comparison of the bioavailability and pharmacokinetic profile of GA indicated that the test and reference capsules were bioequivalent.     

Sensitization to kappa opioid mechanisms associated with tolerance to the anorectic effects of cathinone

To evaluate the possibility that tolerance to the anorectic effects of cathinone (CATH), an amphetamine-like compound, involves the sensitization of endogenous kappa opioid mechanisms, the influence of chronic treatment with CATH on the effects of the selective kappa opioid agonist U50488H (U50) on food and water intake was evaluated in rats. Since kappa agonists specifically increase urine output, the interaction between CATH and U50 on this physiological function was also evaluated. Acutely, CATH produced anorexia and diuresis, whereas water intake was not affected. U50 resulted in an increase in both food and water intake as well as urine output. After 9 days of daily CATH, tolerance to its anorectic effects had developed. In addition, water intake, which was not affected acutely by CATH, was significantly enhanced with respect to controls treated daily with water. In a group treated chronically with U50, its diuretic effect was unchanged, but water intake was no longer increased after 9 days of treatment. Food intake in this group remained higher than control intake for at least 19 days, but this hyperphagic effect was not detectable on day 34. On days 10 and 20 of the chronic regimen, the administration of U50 to the chronic CATH group resulted in a doubling of the hyperphagic response to U50, and this effect was naloxone-reversible. Water intake was also increased but to a lesser extent. The diuretic effect of U50 did not appear to be influenced by chronic CATH administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of gender differences in endothelium-independent dilation using peripheral arterial tonometry

Background: A change in peripheral arterial tonometry (PAT) in response to reactive hyperaemia is often used to provide a non‐invasive measure of endothelium‐dependent dilation (EDD). Reactive hyperaemia does not allow one to quantify endothelium‐independent dilation (EID), which is part of overall vascular function. Although most research examining vascular function and cardiovascular disease has focused on EDD, there is evidence that cardiovascular risk factors may impair EID. Purpose: To examine the microvascular vasodilation response to nitroglycerin (NTG) in healthy adults using PAT. Methods: Microvascular responses to reactive hyperaemia and NTG were evaluated in 86 (41 female and 45 male) healthy subjects (age 37 ± 5 years). Beat‐to‐beat plethysmographic measurements of finger arterial pulse waves were recorded for 5 min following reactive hyperaemia. After a 10‐min rest period, sublingual NTG (0·4 mg) was administered and PAT signal changes were measured for 10 min. Peak reactive hyperaemic index (RHI) and peak NTG‐mediated index (NMI) were determined in all subjects. Results: There were no significant gender differences in peak RHI (females: 2·07 ± 0·56 versus males: 1·91 ± 0·58, P = 0·20). Mean peak NMI for all subjects was 2·78 (±1·49). Peak NMI was significantly greater in females than in males (3·11 ± 1·59 versus 2·50 ± 1·34, P = 0·05). Time to peak NMI was not significantly different between genders (7 min, 28 s [±1 min, 47 s], versus 7 min, 14 s [±1 min, 49 s], P = 0·58). Conclusion: In this population of healthy adults, peak NMI was significantly greater in females than in males. These findings suggest that gender differences exist in the microvascular vasodilation responses to NTG using PAT.     

Seroimmunological monitoring of Campylobacter pylori in patients with cystic fibrosis

The prevalence of infection with Campylobacter pylori (CP) was investigated in patients with cystic fibrosis (CF). Serum IgG antibodies against C. pylori were determined by an indirect ELISA in 263 patients with CF (131 males, 132 females, age 3 months to 33 years, mean age 13·0 ± 7·9 years) and 168 non-CF controls (78 males, 90 females, age 1 week to 32 years, mean age 15·0 ± 8·8 years). A third group consisted of 65 adult non-CF patients (30 males, 35 females, age 18 to 80 years, mean age 41·8 ± 10 years) who had undergone routine endoscopy and were found to present normal gastroduodenal histology and to be C. pylori-negative.The prevalence of serologically-positive sera (specific IgG > 95% upper limits of the C. pylori-negative patients) was comparable for the CF-patients and the non-CF group in all age groups except between the ages of 20 and 24 years. CF-patients chronically colonized with Pseudomonas aeruginosa did not show higher antibody titers against C. pylori than non-colonized CF-patients.For this reason, the prevalence of the CP-infection in CF-patients does not seem to be more frequent than in the non-CF population. The frequent and extended use of antimicrobials for prophylaxis as therapy in CF therefore does not decrease the prevalence of elevated serum antibodies against C. pylori, although the majority of the antibiotics usually applied to CF-patients (eg. oral cephalosporins, erythromycin, 4-quinolones) show high in vitro activity against C. pylori.     

Normovolemia defined according to cardiac stroke volume in healthy supine humans

Background: Both hypovolemia and a fluid overload are detrimental for outcome in surgical patients but the effort to establish normovolemia is hampered by the lack of an operational clinical definition. Manipulating the central blood volume on a tilt table demonstrates that the flat part of the Frank‐Starling curve is reached when subjects are supine and that finding may be applicable for a clinical definition of normovolemia. However, it is unknown whether stroke volume (SV) responds to an increase in preload induced by fluid administration. Methods: In 20 healthy subjects (23 ± 2 years, mean ± SD), SV was measured by esophageal Doppler before and after fluid administration to evaluate whether SV increases in healthy, non‐fasting, supine subjects. Two hundred millilitres of a synthetic colloid (hydroxyethyl starch, HES 130/0·4) was provided and repeated if a ≥10% increment in SV was obtained. Results: None of the subjects increased SV ≥10% following fluid administration but there was a minor increase in mean arterial pressure (92 ± 15 to 93 ± 12 mmHg, P = 0·01), while heart rate (HR) (66 ± 12 beats min^?1; P = 0·32), cardiac output (4·8 ± 1·1 l min^?1; P = 0·25) and the length of the systole corrected to a HR of 60 beats/min (corrected flow time; 344 ± 24 ms; P = 0·31) did not change. Conclusion: Supporting the proposed definition of normovolemia, non‐fasting, supine, healthy subjects are provided with a preload to the heart that does not limit SV suggesting that the upper flat part of the Frank‐Starling relationship is reached.     

Determinants of post-ischaemic reactive hyperaemia in patients with diabetes mellitus type II

Dysfunction of resistance arteries is thought to be an early reversible stage in the development of atherosclerosis. Dynamics of post-ischaemic reactive hyperaemia are believed to constitute a useful tool for monitoring resistance vessel function. Patient characteristics influencing reactive hyperaemia, however, need to be defined more precisely. Since reactive hyperaemia is a dynamic process, yielding submaximal peak values after 5 min of ischaemia, this period was chosen to investigate the determinants of reactive hyperaemia in 100 type II diabetic patients as well as in 61 control subjects. Reactive hyperaemia was measured by venous-occlusion plethysmography; clinical and laboratory data were acquired by routine methods. Statistical comparison was performed with SYSTAT 5·0 for Apple Macintosh. Overall, no significant differences between diabetic patients and controls were observed by group comparison. In control subjects, only gender showed an influence on peak reactive hyperaemia (females 40·5 ± 15·3; males 51·8 ± 17·7 ml min^–1 100 ml^–1, P<0·01). In diabetic patients, in addition to gender, actual blood glucose (r=0·377, P<0·05) and meal intake (non-fasting 42·8 ± 19·2; fasting 51·2 ± 19·5 ml min^–1 100 ml^–1, P<0·05) were found to influence reactive hyperaemia. Further investigation revealed a loss of the correlation between peak reactive hyperaemia and actual blood glucose observed in the fasting state (P<0·001) in non-fasting diabetic patients, indicating an influence of meal intake on resistance vessel reactivity. Our results suggest that, in diabetic subjects, in addition to gender actual blood glucose and the postprandial situation impacts on peak reactive hyperaemia.     

Maintaining oral hydration in older adults: a systematic review

Dehydration is the most common fluid and electrolyte imbalance in older adults. The objectives were to identify the factors that increase the risk of dehydration in older adults, how best to assess the risk and manage oral fluid intake. Data sources included Medline, CINAHL, Cochrane Library, Embase and Current Contents, which were searched until February 2002. Randomized controlled trials for management of adequate fluid intake were undertaken. Cohort and case control studies were used for the identification of risk factors for dehydration. Studies of assessment tools for the identification of dehydration were also considered. Results show that there is no clear determination of the risk factors for dehydration and decreased fluid intake. The recommended daily intake of fluids should be not less than 1600 mL/24 h in order to ensure adequate hydration. A fluid intake sheet and urine specific gravity might be the best methods of monitoring daily fluid intake. Regular presentation of fluids to bedridden older adults can maintain adequate hydration status. In conclusion, more research is required to determine the optimum method of maintaining adequate oral hydration in older adults.     

Day‐to‐day variation in oxygen consumption at submaximal loads during ergometer cycling by adolescents

The day‐to‐day variation in oxygen consumption (V˙O₂) during ergometer cycling by 20 healthy adolescents, 10 females and 10 males, was measured using indirect calorimetry. The two sets of measurements were performed on two consecutive days. Great care was taken to minimize possible disturbing factors. Cycling started at 50 and 100 W for female and male adolescents, respectively. The load was increased at a rate of 5 W 30 s^?1. In order to reach steady state, the load was kept constant for 3·5 min twice during the cycling session, at 100 and 130 W for the females and at 130 and 160 W for the males. Cycling continued until exhaustion. The maximal loads were 196 W (mean) and 271 W (mean) for females and males, respectively. At the maximal loads the day‐to‐day variation (±2 SD) in oxygen consumption (V˙O₂) was ±330 ml min^?1 for females and 390 ml min^?1 for males. At the submaximal loads the day‐to‐day variation in heart rate (HR) was 9·3 beats min^?1 (±2 SD) (coefficient of variation, CV=3·4% at 130 W) for both sexes. The day‐to‐day variation in oxygen consumption (V˙O₂) was ±199 ml min^?1 (±2 SD) at the different submaximal loads and did not differ between female and male adolescents (CV=5·7% at 130 W). This natural day‐to‐day variation must be taken into consideration when using a submaximal ergometer cycling test for the evaluation of physical capacity in the two sexes.     

Preliminary experience with nesiritide in pediatric patients less than 12 months of age

The natriuretic peptide system plays an active role in the regulation of fluid balance and systemic vascular resistance. Advances in recombinant technology have provided the opportunity for the exogenous administration of a recombinant form of B-type natriuretic peptide (nesiritide). To date, reports of its use in the pediatric population are limited, with limited information regarding its use in patients less than 12 months of age. We retrospectively reviewed our experience with nesiritide in infants less than 12 months of age to determine its efficacy and adverse effect profile. The study cohort included 22 patients, ranging in age from 4 days to 12 months. The starting dose of the nesiritide infusion ranged from 0.01 to 0.05 microg/kg/min (0.015+/-0.01microg/ kg/min) and was administered for a total of 3 to 264 hours (85.2+/-75.0 hours). Nesiritide resulted in a significant increase in urine output even in the face of decreased fluid intake. Mean urine output increased from 3.1+/-2.5 mL/kg/h before nesiritide to 5.7+/-4.5 mL/kg/h (P = .03) during the initial 24 hours after starting the infusion. Fluid intake before and after the infusion were 126 +/- 60 mL/kg/d and 108+/-56 mL/kg/d, respectively. There were no statistically or clinically significant changes in hemodynamic parameters (heart rate, blood pressure, and central venous pressure) during the nesiritide infusion. No change in electrolytes, blood urea nitrogen, and creatinine were noted. No adverse effects of the nesiritide infusion were noted. No infusion was stopped due to adverse effects. These data suggest that nesiritide is a safe method of improving urine output in pediatrics patients less than 12 months of age and that the adverse effect profile does not appear to be different than that reported in older children.     

Plasma and urinary leukotrienes in sickle cell disease: possible role in the inflammatory process

Abstract. Sickle cell (HbSS) disease is associated with rheological and inflammatory stresses within the microcirculation. In order to determine the role of leukotrienes in the inflammatory processes in HbSS patients, we analysed plasma and urine levels of leukotrienes (LT); LTB₄, LTC₄, LTD₄, and LTE₄ as indicators of their in vivo metabolism. Plasma and urine level samples of 15 HbSS patients in steady-state and age-matched healthy, homozygous (HbAA) controls were extracted for leukotrienes and quantitated by HPLC. Control plasma level of leukotrienes (mean ± SEM, ng ml^-1) were: LTB₄, 8·95 ± 0·26; LTC₄, 7·24 ± 0·21; LTD₄, 11·42 ± 0·40; and LTE₄, 14·51 ± 0·50. Corresponding values for HbSS patients were: LTB₄, 6·15 ± 0·42; LTC₄, 13·61 ± 1·45; LTD₄, 6·44 ± 0·51 and LTE₄, 4·97 ± 0·37. The differences were significant at P < 0·05. Urine levels (mean ± SEM, ng mmol^-1 creatinine), for controls were: LTB₄, 10·60 ± 0·35; LTC₄, 360·0 ± 9·82. Values for HbSS urine were: LTB₄, 27·50 ± 3·33; LTC₄, 356·0 ± 17·87; LTD₄, 69·90 ± 14·51. LTD₄ was not detected in control urine. These results suggest that sickle cell patients may exhibit impaired ability to catabolize LTC₄ in plasma during steady state conditions. This altered metabolism may contribute to the persistent stress of the microcirculation, and is probably related to the abnormal microvascular rheology of sickle blood cells.