Adenoid hypertrophy affects screening for primary ciliary dyskinesia using nasal nitric oxide.

AIM: In patients with primary ciliary dyskinesia (PCD), the release of nitric oxide (NO) is extremely low by epithelia of the nasopharynx and sinuses. Measurement of nasal NO (nNO) is recommended as a screening test for PCD. The study aimed to evaluate if adenoids affects nNO and may deteriorate the performance of the test. METHODS: In 48 nonallergic patients between 5 and 18 years of age with chronic symptoms of nasal obstruction and indications for adenoidectomy, the measurements of nNO by chemiluminescence analyser and nasal patency by active anterior rhinomanometry were performed both before and after adenoidectomy. Adenoidal tissue size was graded during surgery under general anaesthesia using transoral endoscopy. RESULTS: Patients were stratified into groups with adenoids grades 1, 2 and 3 (<1/3, 1/3-2/3 and > 2/3 of the choana and post-nasal space covered by adenoids). Before adenoidectomy, the median of nNO decreased with the increasing grade of adenoids (920, 663, and 491 ppb, P < 0.05). The rhinomanometry results were comparable and showed no correlation with nNO. Seven patients (14.6%) were incorrectly classified to have PCD based on a subthreshold value of the volume flow of nNO (FnNO < 77 nL/min). Following adenoidectomy, nNO of the grade 3 patients increased by 107 ppb (P < 0.05) and no differences were found between groups (P = 0.40). All patients had the postadenoidectomy FnNO >77 nL/min. CONCLUSIONS: nNO and FnNO are reduced in nonallergic children with obstructive adenoids. Adenoid hypertrophy can potentially cause a false positive result of the test for PCD.

Alveolar concentration and bronchial flux of nitric oxide: two linear modeling methods evaluated in children and adolescents with allergic rhinitis and atopic asthma.

OBJECTIVE: Alveolar concentration (C(A)NO) and bronchial flux (J(aw)NO) of nitric oxide (NO) characterize the contributions of peripheral and proximal airways to exhaled NO. Both parameters can be estimated using a two-compartment model if the fraction of NO in orally exhaled air (FE(NO)) is measured at multiple constant expiratory flow rates (V). The aim of this study was to evaluate how departures from linearity influence the estimates of C(A)NO and J(aw)NO obtained with the help of linear regression analysis of the relationships between FE(NO) and 1/V (method P), and between the NO output (V(NO) = FE(NO) × V) and V (method T). Furthermore, differences between patients with atopic asthma (AA) and allergic rhinitis (AR) and between methods P and T were assessed. DESIGN: Measurements of FE(NO) were performed with a chemiluminiscence analyzer at five levels of V ranging from 50 to 250 ml/sec in school children and adolescents with mild to moderate-severe AA treated by inhaled corticosteroids (N = 42) and AR (N = 20). RESULTS: Violation of the linearity condition at V ≤ 100 ml/sec caused shifts between methods with regard to the partition of exhaled NO into alveolar (C(A)NO: P > T) and bronchial (J(aw)NO: T > P) components. Both methods gave similar results in the linear range of 150-250 ml/sec: The mean ratios P/T and limits of agreement calculated in AA and AR patients were 1.03 (0.49-1.56) and 1.07 (0.55-1.59) for C(A)NO and 1.03 (0.73-1.33) and 0.99 (0.90-1.10) for J(aw)NO, respectively. No significant differences between AA and AR were found in C(A)NO and J(aw)NO calculated in the linear range by the T method {medians (inter-quartile ranges): 1.7 ppb (0.9-3.9) vs. 2.3 ppb (0.8-3.7), P = 0.91; 1,800 pl/sec (950-3,560) vs. 1,180 pl/sec (639-1,950), P = 0.061}. However, the flow-dependency of the estimates was markedly higher in AA than in AR patients: C(A) NO was decreased 2.8-fold vs. 1.5-fold and J(aw) NO was increased 1.5-fold vs. 1.2-fold in the linear range as compared to the range of 50-250 ml/sec. In both groups, the median standard errors (SE) of the J(aw) NO estimates were similar for the metods P and T and small (<15%) regardless of the range for expiratory flows. The precision of C(A) NO estimates was less in all ranges. For both methods, the SE of the estimates obtained in the range of 150-250 ml/sec exceeded 50% in asthmatics and 30% in AR patients, respectively. The results show that FE(NO) has to be measured at several expiratory flows ≥100 ml/sec for the accurate estimation of C(A) NO and J(aw) NO using linear methods P and T in children and adolescents with AA and AR. A stepwise procedure for detecting nonlinearity and evaluating the quality of FE(NO) measurements is suggested.

A comparative study of pharmacokinetics, urinary excretion and tissue distribution of platinum in rats following a single-dose oral administration of two platinum(IV) complexes LA-12 (OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) and satraplatin (OC-6-43)-bis(acetato)amminedichloro(cyclohexylamine)platinum(IV).

PURPOSE: This study compared the pharmacokinetics, tissue distribution, and urinary excretion of platinum in rats after single oral doses of LA-12 and satraplatin. METHODS: Both platinum derivatives were administered to male Wistar rats as suspensions in methylcellulose at four equimolar doses within the range of 37.5-300 mg LA-12/kg body weight. Blood sampling was performed until 72 h, and plasma and plasma ultrafiltrate were separated. Moreover, urine was collected until 72 h, and kidney and liver tissue samples were obtained at several times after administration. Platinum was measured by atomic absorption spectrometry. The pharmacokinetics of platinum was analyzed by population modelling and post hoc Bayesian estimation as well as using non-compartmental pharmacokinetic analysis of the mean concentration-time curves. RESULTS: Platinum was detected in all plasma and ultrafiltrate samples 15 min after oral administration of both compounds and peaked between 3-4 h and 1-3 h, respectively. Similar for LA-12 and satraplatin, the C (max) and AUC values of plasma and ultrafiltrate platinum increased less than in proportion to dose. The mean C (max) and AUC values of plasma platinum observed after administration of LA-12 were from 0.84 to 2.5 mg/l and from 20.2 to 75.9 mg h/l. For ultrafiltrate platinum, the corresponding ranges were 0.16-0.78 mg/l and 0.63-1.8 mg h/l, respectively. The AUC of plasma platinum was higher after satraplatin (P < 0.001). However, administration of LA-12 resulted in significantly higher AUC values of ultrafiltrate platinum after the doses of 150 mg and 300 mg/kg (P < 0.01), respectively, and the C (max) values were significantly higher starting from the dose of 75 mg/kg LA-12 and upward (P < 0.01). Cumulative 72-h urinary recovery of platinum dose was below 5% for both compounds, and it decreased with the dose of satraplatin (P < 0.01), while a numerical decrease was observed after administration of LA-12 that did not reach statistical significance (P = 0.41). The renal clearance of free platinum was similar regardless of the dose and compound administered. Platinum concentrations in the liver homogenate exceeded those in the kidney. Distribution of platinum to tissues was higher after LA-12 compared to satraplatin. The difference in kidney platinum increased with dose and was twofold after 350 mg/kg LA-12. Liver platinum was twofold higher after LA-12 across all four doses. CONCLUSIONS: In conclusion, this first comparative pharmacokinetic study with LA-12 and satraplatin shows that characteristics of platinum exposure evaluated in the plasma, plasma ultrafiltrate and kidney and liver tissues increase less than in proportion to dose following a single-dose administration of 37.5-300 mg/kg to Wistar rats. These findings together with the dose-related elevation in the pharmacokinetic characteristics V/F and CL/F of platinum and ultrafiltrate platinum as well as a drop in platinum urinary recovery are consistent with a dose-related decrease in the extent of oral bioavailability most likely due to saturable intestinal absorption.

Nitrite in exhaled breath condensate as a marker of nitrossative stress in the airways of patients with asthma, COPD, and idiopathic pulmonary fibrosis.

BACKGROUND: Nitrite and nitrate are exhaled in droplets of an aerosol during breathing and can be assayed in the exhaled breath condensate (EBC) as markers of nitrossative stress in the airways of patients with asthma, COPD, and idiopathic pulmonary fibrosis (IPF). SUBJECTS AND METHODS: Using HPLC with fluorescence detection, nitrite and nitrate were assayed in EBC of 14 atopic patients with mild-to-moderate stable asthma, 18 atopic asthmatics with exacerbation, 14 COPD patients without exacerbation, 18 patients with exacerbated COPD, 13 patients with active IPF, and in 29 healthy subjects. RESULTS: The geometric mean [exp(mean±SD)] EBC concentrations of nitrite (micromol/l) in patients with asthma [5.1(2.1-12.3)], exacerbation of asthma [5.1(2.8-9.6)], exacerbation of COPD [5.3(3.2-8.7)], and with IPF [5.5(2.9-10.2)] were higher (P<0.05) compared with those of healthy subjects [2.9(1.6-5.3)] and patients with stable COPD [3.0(1.3-6.7)]. Nitrite concentration increased with decreased lung function of patients with asthma (r(s)=-0.31, P<0.02). Presumably owing to the contamination of the EBC sample with nitrate during collection, nitrate levels were highly variable among healthy subjects and higher compared with all groups of patients. CONCLUSION: EBC nitrite is a suitable marker of nitrossative stress in adult patients with lung diseases but cannot differentiate controlled and exacerbated asthma. Further improvements to the methods of EBC collection and sample handling are warranted.

High-dose methotrexate in children with acute lymphoblastic leukemia: 7-hydroxymethotrexate systemic exposure and urinary concentrations at the steady state correlate well with those of methotrexate.

The present study evaluated the pharmacokinetics of methotrexate (MTX, CAS 59-05-2) and 7-hydroxymethotrexate (7-OHMTX, CAS 5939-37-7) in children with acute lymphoblastic leukemia (ALL) with particular interest devoted to the renal excretion at the steady-state and to the relationships between total (CL) and renal clearances (CL(R)) of both compounds. Ten children (seven girls) aged 8.5 years (2.9-16) years with standard or medium-risk ALL received four 24-h i.v. infusions of high-dose MTX (HDMTX, 5 g/m2) with leucovorin (CAS 58-05-9) rescue according to the ALL-BFM-95 protocol. MTX and 7-OHMTX were assayed in plasma and urine by high-performance liquid chromatography. At the steady-state, the clearance (CL) of MTX (6.28 +/- 2.79 l h(-1)) was correlated with its CL(R) (r(s) = 0.79, p < 0.0001) which accounted for 61% (SD 26%) of the former. There were weak correlations between pretreatment values of creatinine clearance calculated using Schwartz's formula and the drug's CL (r(s) = 0.30, p < 0.05) or CLR (r(s) = 0.41, p < 0.02). In contrast, the CL(R) accounted for only 26% (SD 15%) of the metabolite's CL which was estimated assuming 10% conversion of MTX to 7-OHMTX. The CL values of both compounds were highly correlated (r(s) = 0.86, p < 0.0001). The CL(R) of the parent compound was on the average 9-fold higher (range: 3.5- to 17-fold) and was strongly correlated with the CL(R) of the metabolite (r(s) = 0.87, p < 0.0001). The ratio 7-OHMTX/MTX of urinary concentrations was between 2.4 and 9.8% with the mean value of 4.1%. This study suggests that during the 24-h i.v. infusions of HDMTX to children with ALL, the exposure of patients to 7-OHMTX can be reasonably well predicted from the knowledge of MTX concentrations. The steady-state renal CLs, total CLs as well as urinary concentrations of the parent compound and metabolite are highly correlated and the correlation of plasma concentrations is moderate. Therefore, it is unlikely that simultaneous evaluation of 7-OHMTX and MTX steady-state concentrations could improve the predictive performance of the latter towards the response or the risk of complications, although future larger studies should verify this conclusion.

Tolerability and outcomes of kinetically guided therapy with gentamicin in critically ill neonates during the first week of life: an open-label, prospective study.

BACKGROUND: Aminoglycosides are bactericidal antibiotics used worldwide for the treatment of serious infections in critically ill patients, including neonates. Critically ill neonates constitute a unique challenge in dosing owing to the pathologic alterations that accompany severe illness and the rapidly changing conditions of these patients. OBJECTIVES: The main objective of this study was to analyze the kinetically guided dosage adjustment of gentamicin in neonates critically ill during the first week of life based on plasma concentrations after the first dose and to identify the impact of covariates (eg, fluid intake, body fluid retention) with respect to gestational age (GA). Tolerability of therapy was also assessed. METHODS: This 10-day, open-label, prospective study included neonates critically ill during the first week of life admitted to the neonatal intensive care unit of a children's hospital between January 2006 and July 2009. Hearing and renal assessments were conducted over a 24-month follow-up period. The patients were treated with gentamicin for suspected sepsis, proven sepsis, or pneumonia as an early sign of sepsis. The first and second doses of gentamicin 4 mg/kg were adjusted according to birth weight and GA: group 1 (GA < 34 weeks), 48-hour interdose intervals; group 2 (GA 34-38 weeks), 36 hours; and group 3 (GA > 38 weeks), 24 or 48 hours. Individual pharmacokinetic parameters were estimated after the first dose (given in 30-minute intravenous infusions) using 4 concentrations. Individual pharmacokinetic parameters were estimated by fitting the parameters of a 2-compartment model into 4 concentrations. The last 2 blood samples were taken 30 minutes before the fourth infusion (C(trough,3)) and 1 hour after its start (C(max,4)). Dosing was individualized to reach target ranges for the C(trough,3) (0.5-2.0 mg/L) and C(max,4) (6-10 mg/L) values. If needed, initial dosing was changed after the second dose by adjusting (reducing or increasing) the third and subsequent doses, or by adjusting (prolonging or shortening) the interdose intervals. C(trough,3) and C(max,4) were assessed to determine differences between predicted and assayed values. Fluid retention was registered as the difference between fluid intake and urine output at different intervals related to the first dose per kilogram of birth weight, and from the start of the first infusion (0 hour) to the day of the fourth infusion. The C(max)/minimum inhibitory concentration (MIC) ratio was determined for assessment of optimal response. Tolerability was evaluated during the 24-month follow-up period using renal sonography to screen for nephrocalcinosis and transient evoked otoacoustic emission recordings to evaluate hearing abnormalities. RESULTS: A total of 84 neonates (all white; 53 males, 31 females; birth weight range, 0.8-4.56 kg; GA range, 24-42 weeks) were enrolled in 3 groups: group 1, GA < 34 weeks, n = 27; group 2, GA 34-38 weeks, n = 22; and group 3, GA > 38 weeks, n = 35. The C(max) value detected 1 hour after the start of the first infusion (C(max,1)) reached the target range of 6-10 mg/L in 66 of the 84 neonates (79%). After the initial dose, C(max,1) was variable (%CV, 29%); the failure rate to reach 6 mg/L was 13%. V(d) decreased with GA (r = -0.30, P < 0.01) and achieved mean (SD) rates of 0.51 (0.10), 0.48 (0.13), and 0.40 (0.15) L/kg in groups 1, 2, and 3, respectively. Neither C(max) nor V(d) was correlated with fluid intake relative to the first infusion. Mean gentamicin clearance measured after dose 1 (0.47 [0.23], 0.66 [0.26], and 0.76 [0.32] mL/min/kg) increased with GA (r = 0.45, P < 0.001). The interdose interval was prolonged after the second and subsequent infusions in 8 of 84 neonates (10%) or by decreasing the third dose and subsequent doses in 51 neonates (61%). The target C(max,4) and C(trough,3) values occurred in 63% (22 of 35) and 83% (29 of 35) of full-term patients (GA >38 weeks), respectively. In preterm neonates, the target range for C(max,4) was reached in 11 of 27 patients (41%) in group 1 and 11 of 22 patients (50%) in group 2; for C(trough,3), the target range was reached in 25 patients (93%) in group 1 and in 16 (73%) in group 2. C(trough,3) >2 mg/L was detected in 1 full-term neonate, and gentamicin was withdrawn. Suspected fluid retention within the time period of 0 hour to the day of the fourth infusion was well correlated with actual body weight (r = 0.58, P < 0.001), but it was negatively correlated with C(max,4) (r = -0.25, P = 0.02). Thirteen of the 84 neonates (15%) had confirmed sepsis. C(max)/MIC was >12 except for 2 resistant staphylococcal infections (C(max)/MIC = 0.4); amikacin and vancomycin were substituted for gentamicin in these cases. Clinical signs and laboratory data indicative of suspected sepsis disappeared in 5 to 10 days in 68 of 71 neonates. In 1 neonate, gentamicin was withdrawn after dose 4 because of a high C(trough,3) value. In the 3 remaining neonates, C-reactive protein was decreased >10 days without changing therapy. Two neonates died, 1 of severe hypoxic-ischemic encephalopathy as a consequence of perinatal asphyxia and another of stage IV intraventricular hemorrhage. Transient renal dysfunction attributable to gentamicin was detected in 1 case. No signs of late toxicity (nephrocalcinosis) were found during the second year of follow-up. Two neonates were diagnosed with unilateral hearing loss, a secondary phenomenon of hypoxic-ischemic encephalopathy thought to be related to the severe perinatal asphyxia. CONCLUSIONS: The initial dose of gentamicin 4 mg/kg for these critically ill premature and mature neonates with sepsis during the first week of life was high enough to reach bactericidal C(max,1) within 6-10 mg/L. C(max,1) <6 mg/L occurred in 13% of neonates. The interdose interval modified according to the recommendation resulted in C(trough) values within the target range of 0.5-2.0 mg/L in all but 2 neonates. The kinetically guided maintenance dosing of gentamicin based on plasma concentrations after the first dose should be optimized, taking into account actual body weight. (EudraCT number: 2005-002723-13).

Analysis of single-breath profiles of exhaled nitric oxide in children with allergy and asthma: guideline-derived plateau concentrations compared to results of automatic evaluation by two analyzers.

Current guidelines recommend the single-breath measurement of fractional concentration of exhaled nitric oxide (FE(NO)) at the expiratory flow rate of 50 mL/s as a gold standard. The time profile of exhaled FE(NO) consists of a washout phase followed by a plateau phase with a stable concentration. This study performed measurements of FE(NO) using a chemiluminescence analyzer Ecomedics CLD88sp and an electrochemical monitor NIOX MINO in 82 children and adolescents (44 males) from 4.9 to 18.7 years of age with corticosteroid-treated allergic rhinitis (N = 58) and/or asthma (N = 59). Duration of exhalation was 6 seconds for children less than 12 years of age and 10 seconds for older children. The first aim was to compare the evaluation of FE(NO)-time profiles from Ecomedics by its software in fixed intervals of 7 to 10 seconds (older children) and 2 to 4 seconds (younger children) since the start of exhalation (method A) with the guideline-based analysis of plateau concentrations at variable time intervals (method B). The second aim was to assess the between-analyzer agreement. In children over 12 years of age, the median ratio of FE(NO) concentrations of 1.00 (95% CI: 0.99-1.02) indicated an excellent agreement between the methods A and B. Compared with NIOX MINO, the Ecomedics results were higher by 11% (95% CI: 1-22) (method A) and 14% (95% CI: 4-26) (method B), respectively. In children less than 12 years of age, the FE(NO) concentrations obtained by the method B were 34% (95% CI: 21-48) higher and more reproducible (p < 0.02) compared to the method A. The Ecomedics results of the method A were 11% lower (95% CI: 2-20) than NIOX MINO concentrations while the method B gave 21% higher concentrations (95% CI: 9-35). We conclude that in children less than 12 years of age, the guideline-based analysis of FE(NO)-time profiles from Ecomedics at variable times obtains FE(NO) concentrations that are higher and more reproducible than those from the fixed interval of 2 to 4 seconds and higher than NIOX MINO concentrations obtained during a short exhalation (6 seconds). The Ecomedics FE(NO) concentrations of children more than 12 years of age calculated in the interval of 7 to 10 seconds represent plateau values and agree well with NIOX MINO results obtained during a standard 10-second exhalation.

The effect of folic acid supplementation on the pharmacokinetics and pharmacodynamics of oral methotrexate during the remission-induction period of treatment for moderate-to-severe plaque psoriasis.

OBJECTIVE: We assessed the effect of folic acid (FA) on the pharmacokinetics and pharmacodynamics of low-dose oral methotrexate (MTX) during the remission-induction phase of psoriasis treatment. METHODS: In a 32-week, open-label, two-way cross-over study, patients (n=20, seven men, aged 35-70 years) with moderate-to-severe plaque psoriasis were randomly assigned to receive MTX plus FA (20 mg/week) for 16 weeks followed by MTX monotherapy (three doses of MTX separated by 12-h intervals once a week) for an additional 16 weeks (treatment arm A, n=10) or to receive the opposite sequence of treatments (arm B, n=10). Dosing of MTX was individualised with the help of pre-study evaluation of plasma MTX pharmacokinetics. The Psoriasis Area and Severity Index (PASI), biochemistry and haematology tests and erythrocyte concentration of MTX polyglutamates (MTXPG) were evaluated throughout the study. RESULTS: In arms A and B, the mean (range) concentrations of MTXPG (nmol/L) were comparable [week 16: 96.2 (32.0-157) vs. 111 (73.7-175), P=0.32; week 32: 103 (55.8-173) vs. 83.6 (27.4-129), P=0.24]. After 16 weeks, the mean+/-SEM PASI decreased from 20.1+/-2.1 to 8.8+/-1.3 in arm A, while a greater reduction from 27.2+/-2.1 to 5.1+/-1.0 occurred in arm B (P<0.001). Positive correlations were found between the percent improvement in PASI at week 16 and the ratios of the concentration of MTXPG to plasma folate (rho=0.59, P=0.008) or RBC folate concentration (rho=0.56, P=0.013). Due to an accelerated decline in PASI in arm A and a trend to its worsening in arm B after crossing over of treatments, the mean absolute PASI scores in both arms were comparable at week 32. CONCLUSION: The antipsoriatic effect of MTX during the remission-induction phase of treatment is influenced by folate status and may be significantly less if combined treatment with FA is used, irrespective of pre-treatment folate levels. The individual tailoring of MTX dosing needs further attention because the mean percent PASI improvement from baseline was 83% and the inter-patient variability in response was low after 16 weeks of monotherapy with MTX.

Validation of nitrite and nitrate measurements in exhaled breath condensate.

BACKGROUND: Inflammatory markers in exhaled breath condensate (EBC) are investigated as a non-invasive approach to monitoring of inflammation in the respiratory tract. EBC concentrations of nitrite and nitrate, the stable end products of oxidative metabolism of nitric oxide, are increased in patients with asthma, especially during acute exacerbations. OBJECTIVES: To examine methodological aspects of nitrite and nitrate measurements in EBC such as sample collection, storage and analysis. METHODS: In a randomized study, EBC was collected twice within 1 h (with and without a nose clip) in 20 healthy adults and 20 patients with well-controlled asthma and no symptoms of allergic rhinitis. Nitrite and nitrate were assayed by ionex chromatography and fluorimetrically after derivatization with diaminonaphthalene. RESULTS: The geometric mean [exp (mean +/- SD)] EBC levels of nitrite and nitrate in healthy subjects [4.3 (3.0-6.1) and 11.0 (5.3-22.7) micromol/l] and patients [4.6 (2.6-7.3) and 8.7 (3.2-23.8) micromol/l] did not differ (p = 0.13). Wearing a nose clip (p = 0.3) did not influence nitrite and nitrate concentrations. The mean intra-subject %CVs of EBC concentrations of nitrite were 26 and 21% in healthy subjects and patients, while those of nitrate achieved 49 and 88%, respectively. CONCLUSIONS: Ionex chromatography of nitrite and nitrate requires no sample pretreatment and provides comparable results as a more laborious diaminonaphthalene method. EBC samples should be kept cold (8 degrees C) and analyzed for nitrite and nitrate within 24 h of collection or stored in the freezer and thawed preferably only once. Wearing a nose clip during EBC collection has no influence on nitrite and nitrate concentrations. Short-term repeatability of nitrite and nitrate measurements was worse compared to published data on exhaled nitric oxide.