Docosahexaenoic acid (DHA) supplementation in atopic eczema: a randomized, double-blind, controlled trial.

BACKGROUND: The increasing prevalence of atopic eczema has been linked to the alteration of the Western diet, namely the reduced consumption of omega-3 (n-3) polyunsaturated fatty acids (PUFA) and an increased omega-6 (n-6) PUFA intake. OBJECTIVES: The aim of the pilot study was to determine the efficacy of dietary n-3 PUFA docosahexaenoic acid (DHA) in patients with atopic eczema. METHODS: Fifty-three patients suffering from atopic eczema aged 18-40 years were recruited into this randomized, double-blind, controlled trial and received either DHA 5.4 g daily (n = 21) or an isoenergetic control of saturated fatty acids (n = 23) for 8 weeks. At weeks 0, 4, 8 and 20 the clinical outcome was assessed by the SCORAD (severity scoring of atopic dermatitis) index. IgE production and activation of peripheral blood mononuclear cells (PBMC) were analysed. Plasma fatty acids were measured by gas chromatography. RESULTS: DHA, but not the control treatment, resulted in a significant clinical improvement of atopic eczema in terms of a decreased SCORAD [DHA: baseline 37.0 (17.9-48.0), week 8 28.5 (17.6-51.0); control: baseline 35.4 (17.2-63.0), week 8 33.4 (10.7-56.2)]. A significant reduction of anti-CD40/interleukin 4-mediated IgE synthesis of PBMC was detected in the DHA group only. Supplementation led to a modulated activation status of PBMC in both groups. The DHA group showed an increase of plasma n-3 PUFA and a decrease in the n-6/n-3 PUFA ratio. CONCLUSIONS: Our data suggest that dietary DHA could be bioactive and might have a beneficial impact on the outcome of atopic eczema, but our results need to be confirmed in a larger study.

In-vitro investigations evaluating the detection spectrum of cervical lymph nodes via handheld gamma probe.

BACKGROUND: Currently the significance of the sentinel node (SN) biopsy also for head and neck cancer is discussed intensively. Based on the complex anatomic structures of this region with a low distance between primary and sentinel node as well as approximately 300 lymph nodes an intensive discussion of the methodical basis of sentinel node detection seems to be essential. Thus it was the aim of the present study to examine the detection spectrum of a gamma probe for identification of cervical lymph nodes using an in vitro model to describe and objectify the particularities of measurement existing in the head and neck region. MATERIAL/METHODS: In an in vitro model the detection spectrum of a gamma probe is examined in 29 different series of measurements (variation of the specimen filled with 99m pertechnetat regarding activity, position, collimator distance, tissue sheath). RESULTS: The presented in vitro model reflects the clinical problem of narrow intranodal activity of neighbouring lymph nodes and reveals a direct relation between the number of radiation sources and their isolated evidence. Using muscle tissue with a thickness of 0.4 cm, two two-rowed radiation sources, the more powerful is placed 1.5 cm behind the other specimen, with a lateral difference of 3 cm, can be resolved only with a maximal detector distance of 1 cm. Not the difference of the tissue but the thickness of the tissue is decisive for detection. CONCLUSION: Especially for pharyngeal and laryngeal lymph nodes a transcutaneous measurement reflecting the exact localisation of hot nodes in the area of the deep jugular lymph nodes is not possible with increasing tissue thickness. The described results require a critical discussion of the different detection techniques varying among the different working groups of this field.

Surface field activated fragmentation of arginine oligomers.

Protonated arginine oligomers produced by matrix-assisted laser desorption/ionization (MALDI) graze at a kinetic energy of 350 eV along a surface of fluorinated hydrocarbon or mineral oil. The cation fragments activated by excitation processes during the slide on the surface are analyzed by time-of-flight mass spectrometry. The resulting fragment ion mass spectra are interpreted by applying a theoretical concept of excimol accumulation and trap bond dissociation, suggested earlier. According to this theory, energy is accumulated and fragments are formed independently by each arginine residue of a sliding oligomer ion. It is concluded that the observed variation in the fragment ion spectra of the oligomers is a consequence of different oligomer velocities and not a fingerprint of different ion structures.

Intraoperative sentinel node biopsy in patients with squamous cell carcinomas of the head and neck--experiences using a well-type NaI detector for gamma ray spectroscopy.

The sentinel node (SN) biopsy in an actually discussed topic. The use of a well-type NaI detector for gamma ray spectroscopy (WTD) beside the use of a handheld gamma probe (HGP), is investigated. In 18 patients suffering from a head and neck squamous cell carcinoma (HNSCC) with different lymph node status an intraoperative SN biopsy was accomplished with a HGP. 64 separately taken lymph nodes were supplied to an additional measurement in a WTD. A tumor-free SN represented the tumor-free lymph node status in 9 patients. In 5 cases an isolated tumor metastasis could be proven in the SN. SN biopsy has no meaningfullness in cases of advanced metastatic spread ipsilaterally, but possibly in contralateral N0-neck. In 64 separately investigated lymph nodes an activity enrichment could be proven in the WTD. With this procedure small count rates could be determined in contrast to the HGP. The distinction of weakly enriching lymph nodes was less favourable with the HGP but successful with the WTD. The additional use of a WTD offers a more exact distinction of intranodal disintegration rates of the draining lymph nodes. The WTD may increase the security of intraoperative SN biopsy.

Grazing incidence surface-induced dissociation of protonated peptides generated by matrix-assisted laser desorption/ionization.

The grazing incidence surface-induced dissociation (GI-SID) of various protonated peptides with typical kinetic energies of 350 eV was investigated. Peptide ions were generated by matrix-assisted laser desorption/ionization (MALDI) using delayed extraction. The collision target surfaces used were aluminum and a liquid film of perfluorinated hydrocarbons. All peptides studied in these experiments showed enhanced fragment ion yields at grazing incidence (GI-SID effect) as observed in our former experiments with other precursor ion types. In general the GI-SID spectra exhibit N-terminal a(1)-type fragment ions, immonium ions and side-chain fragment ions in the low mass-to-charge region. Fragment ion series of the peptide backbone were not observed, which are typical and abundant in the spectra of established fragmentation techniques like collision-induced dissociation, MALDI post-source decay or surface-induced dissociation at steeper angles. The potential of the GI-SID process to yield useful information for primary structure determination of peptides is indicated by the observed differences in the GI-SID spectra of the isomeric dipeptides LR and IR.

Fragmentation of polyatomic molecules by grazing incidence surface-induced dissociation (GI-SID).

The grazing incidence surface-induced dissociation (GI-SID) of n-hexadecylpyridinium and verapamil ions generated by fission fragment desorption was studied. These molecules show the effect of enhanced surface-induced dissociation at grazing incidence as it was observed in former experiments with metal organic ions. A liquid film of perfluorinated polyether is used as collision surface. Small hydrocarbon fragment ions predominate in the GI-SID spectra. Pyridine ions appear as specific fragment ions in the GI-SID spectrum of n-hexadecylpyridinium. The GI-SID conversion efficiency varies in the range 40-70%. The experimental results are discussed within the scope of a quantum mechanical model which is based on the accumulation of internal molecular energy by resonant excitation of collective vibrational states and energy transfer to a trap bond due to dipole-dipole interactions. In this context the GI-SID spectra of n-hexadecylpyridinium and verapamil ions are compared with the fragmentation occurring in regular (252)Cf plasma desorption mass spectrometry.

Fragmentation of molecules sliding along surfaces in the speed range above thermal and below Bohr velocity.

A theoretical model and experimental time-of-flight mass spectrometric data for the fragmentation of molecules grazing along surfaces at velocities v = 10(5)-10(6) cm/s are presented. The effect of enhanced surface-induced dissociation at grazing incidence (GI-SID) is shown for hexadecylpyridine ions. The velocity dependence of the GI-SID fragmentation probability is studied in experiments with adduct ions of cyclodextrin derivatives. Surfaces used in the various collision experiments are aluminum oxide, gold, and a liquid film of perfluorinated polyether. In the theoretical model of the GI-SID effect we consider polyatomic molecules with substructures consisting of chains of identical biatomic dipoles. Because of the interaction with the periodic Coulomb field of the surface, collective vibrational excitations (excimols) are induced in these chains. Energy accumulation of several excimols and a subsequent energy transfer to a trap bond can induce its dissociation. An analytical expression for the velocity dependent GI-SID fragmentation probability is given, which is in good agreement with the experimental data.

Limited sampling models for reliable estimation of etoposide area under the curve.

Limited sampling models are able to estimate the area under the concentration-time curve (AUC) from plasma concentrations measured at only a few time points. The purpose of this study was to establish a model estimating etoposide AUC independently of specific chemotherapy protocols, underlying malignancies, concomitant diseases and age. Pharmacokinetic parameters were measured in 30 patients treated with polychemotherapy including etoposide (80-150 mg/m2). Etoposide analysis was performed by thin layer chromatography and consecutive quantitative sample detection by 252Cf-plasma desorption mass spectrometry. Data from the first 15 patients formed the training set. Based on the training data, five different models were generated, with the multiple regression coefficient r ranging from 0.91 to 0.96. The following model was selected as "most accurate": AUC = 343 (min)C4h(micrograms/ml) + 650(min)C8h(micrograms/ml) + 1252 (min micrograms/mol), where C4h is the plasma concentration of etoposide at 4 h after the end of infusion and C8h at 8 h. This model was validated on the test set, comprising the data of the remaining 15 patients. The mean predictive error (MPE) was -0.2% and the root mean square predictive error (RMSE) was 4.7%. When used for a large number of patients, this practicable and simple model is an instrument for use in prospective studies, to measure a correlation between drug dosage and efficacy or toxicity of the drug.

Pharmacokinetics of etoposide: correlation of pharmacokinetic parameters with clinical conditions.

The pharmacokinetic parameters of etoposide were established in 35 patients receiving the drug parenterally within the framework of different polychemotherapy protocols. A total of 62 data for 24-h kinetics were analysed. After sample extraction and high-performance liquid chromatography (HPLC) or thin-layer chromatographic (TLC) separation, etoposide was measured by means of [252Cf]-plasma desorption mass spectrometry (PDMS). This highly specific detection system proved to be very practicable and reproducible. The present study comprised two parts that were absolutely comparable in terms of clinical and pharmacokinetic parameters. In part II of the study, sensitivity was improved by modifying the analytical technique. After the exclusion of patients who had previously been given cisplatin or who exhibited renal impairment and of one patient who showed extremely high levels of alkaline phosphatase, gamma-GT and SGPT, the mean values calculated for the pharmacokinetic parameters evaluated were: beta-elimination half-life (t 1/2 beta), 4.9 +/- 1.2 h; mean residence time (MRT), 6.7 +/- 1.4 h; area under the concentration-time curve (AUC), 5.43 +/- 1.74 mg min ml-1; volume of distribution at steady state (Vdss), 6.8 +/- 2.7 l/m2; and clearance (Cl), 18.8 +/- 5.3 ml min-1 m-2. The pharmacokinetic parameters were correlated with 12 different demographic or biochemical conditions. Impaired renal function, previous application of cisplatin and the age of patients were found to influence etoposide disposition to a statistically significant extent. We suggest that the dose of etoposide should be reduced in elderly patients and/or in individuals with impaired renal function, especially in those exhibiting general risk factors such as reduced liver function with regard to the polychemotherapy.

Gridless Ion Acceleration Systems for Time-of-Flight Mass Spectrometry.

Pointlike ion sources allow the application of gridless acceleration systems in time-of-flight mass spectrometry (TOF/MS). When ions are extracted from large sample areas according to the applied ionization method and sample geometry, the application of electrostatic lenses for acceleration seems to be difficult. Inhomogeneous extraction fields are likely to induce acceleration time variations for ions emerging from different locations on the sample. We investigated gridless acceleration systems with the help of computer simulations. An appropriate solution for TOF/MS was found and experimentally tested, combining the features of compactness and a wide-acceptance aperture with simple principles of construction. nt]mis|Dedicated to Ronald D, Macfarlane on the occasion of his 60th birthday.

Pharmacokinetics of high-dose etoposide after short-term infusion.

The pharmacokinetics of high-dose etoposide (total dose, 2100 mg/m2 divided into three doses given as 30-min infusions on 3 consecutive days) were studied in ten patients receiving high-dose combination chemotherapy followed by autologous bone marrow transplantation. In addition to etoposide, all subjects received 2 x 60 mg/kg cyclophosphamide and either 6 x 1,000 mg/m2 cytosine arabinoside (ara-C), 300 mg/m2 carmustine (BCNU), or 1,200 mg/m2 carboplatin. Plasma etoposide concentrations were determined by 252Cf plasma desorption mass spectrometry. In all, 27 measurements of kinetics in 10 patients were analyzed. According to graphic analysis, the plasma concentration versus time data for all postinfusion plasma etoposide values were fitted to a biexponential equation. The mean values for the calculated pharmacokinetic parameters were: t1/2 beta, 256 +/- 38 min; mean residence time (MRT), 346 +/- 47 min; AUC, 4,972 +/- 629 micrograms min ml-1 (normalized to a dose of 100 mg/m2); volume of distribution at steady state (Vdss), 6.6 +/- 1.2 l/m2; and clearance (CL), 20.4 +/- 2.4 ml min-1 m-2. A comparison of these values with standard-dose etoposide pharmacokinetics revealed that the distribution and elimination processes were not influenced by the dose over the range tested (70-700 mg/m2). Also, the coadministration of carboplatin did not lead to significant pharmacokinetic alterations. Although plasma etoposide concentrations at the time of bone marrow reinfusion (generally at 30 h after the last etoposide infusion) ranged between 0.57 and 2.39 micrograms/ml, all patients exhibited undelayed hematopoietic reconstitution.

Drug monitoring of etoposide (VP16-213). Correlation of pharmacokinetic parameters to clinical and biochemical data from patients receiving etoposide.

Pharmacokinetic parameters established in 15 patients receiving parenterally administered etoposide (80-120 mg . m-2) are reported. The etoposide assay by means of mass spectrometry after sample separation by thin-layer chromatography or high-pressure liquid chromatography used in this study has been described elsewhere. Peak plasma levels (9.5-63.3 micrograms . ml-1), the area under the curve (AUC) (2707-10192 micrograms . ml-1 . min-1), the mean transit time MTT (2.7-10.6 h), etoposide half-lives t1/2 alpha (0.10-0.52 h) and t1/2 beta (2.18-8.17 h), the volume of distribution at steady state (Vdss) (2.5-15.1 . l/m-2) and the systemic clearance (Cls) (10.1-35.1 ml min-1 . m-2) with the resulting mean values and standard deviations were determined. Our findings are compared with those of other authors, especially with regard to the method of detection used. This comparison indicates similar individual deviations and shorter half-lives with increasing specificity of the employed assay. Four patients studied on 3 consecutive days and, in one instance, during two different cycles of chemotherapy showed no sign of accumulation or of accelerated excretion of etoposide. There was little intrapatient variability. The pharmacokinetic parameters were correlated to clinical and laboratory findings. Statistical analysis indicated that the AUC was increased by prior cisplatin therapy and in patients with elevated levels of alkaline phosphatase. The Cls was decreased by prior cisplatin therapy, in obese patients, and by elevated alkaline phosphatase. The t1/2 beta of etoposide was increased in older patients. Linear regression analysis yielded a greater Vdss in patients with lower serum albumin levels, but this correlation has not yet been found to be statistically significant.

Combined thin layer chromatography/mass spectrometry: an application of 252Cf plasma desorption mass spectrometry for drug monitoring.

The pharmacokinetic analysis is performed in a three-step procedure: sample extraction, sample purification by thin layer chromatography (TLC) and quantitative sample detection by time-of-flight (TOF) mass spectrometry. 252Cf plasma desorption (PD) mass spectrometry utilizing the fission fragment-induced ionization and desorption of non-volatile compounds is suitable as a universal, non-destructive detector in TLC. Here TLC and mass spectrometry are operated in an off-line combination. As an example some pharmacokinetic data for etoposide (VP 16-213) together with calibration data are presented. The new experimental method is discussed in terms of sensitivity and detection limit.

Drug monitoring of etoposide (VP16-213). I. A combined method of liquid chromatography and mass spectrometry.

Drug monitoring is performed by means of sample extraction, sample purification by high-performance liquid chromatography (HPLC), and sample detection by time-of-flight mass spectrometry. This mass spectrometry utilizing 252Cf fission fragment-induced ionization and desorption of nonvolatile compounds is suitable as a universal, nondestructive detector in HPLC. Liquid chromatography and mass spectrometry are combined, so that mass analysis can be operated online and offline to the fractional sampling of the effluent and the samples can still be recovered. As an alternative to HPLC separation, samples can be purified by thin-layer chromatography (TLC), resulting an offline TLC + MS combination. Preliminary pharmacokinetic data for etoposide (VP16-213) together with calibration data are presented, and are discussed with reference to the sensitivity and detection limit of the new experimental method.