Changes in the activity and protein levels of CSF acetylcholinesterases in relation to cognitive function of patients with mild Alzheimer's disease following chronic donepezil treatment.

OBJECTIVES: To evaluate long-term changes in acetylcholinesterase (AChE) activity in CSF and blood following donepezil treatment in relation to the concentration of donepezil and cognition in AD patients. METHODS: CSF or blood (or both) samples of a total of 104 patients with mild AD were used [MMSE score 23 +/- 0.4; age 75 +/- 1 years (mean +/- SEM); n=53 for CSF and n=51 for plasma/red blood cell (RBC) samples]. The patients were treated with 5 or 10 mg/day donepezil and clinically followed for 2 years. The CSF and RBC AChE activities were measured by the Ellman's direct colorimetric assay. Protein levels of two variants of AChE ("read-through" AChE-R and synaptic AChE-S) were determined by an ELISA-like method. RESULTS: The plasma donepezil concentration was dose-dependent (between 30 and 60 ng/mL in the 5-mg and 10-mg group, respectively). The CSF donepezil concentration was 10 times lower than the plasma level and showed dose- and time-dependent kinetics. The RBC AChE inhibition was moderate (19-29%). CSF AChE-S inhibition was estimated to 30-40% in the 5-mg and 45-55% in the 10-mg group. Positive correlations were observed between the CSF AChE inhibition, an increased protein level of the AChE-R variant and MMSE examination. Patients with high AChE inhibition (>or=45%) showed a stabilized MMSE test result after up to two years, while a significant decline was observed in AD patients with lower AChE inhibition (

Validity of self reports in a cohort of Swedish adolescent smokers and smokeless tobacco (snus) users.

OBJECTIVE: To validate self reports of cigarette and smokeless tobacco (snus) use in a prospective cohort of adolescents. DESIGN: A cross sectional analysis of a cohort sub-sample. SETTING: County of Stockholm, Sweden. SUBJECTS: 520 adolescents in the final grade of junior high school (mean age 15.0 years). MAIN OUTCOME MEASURE: Concordance between self reported tobacco use and saliva cotinine concentration. RESULTS: Using a cut point of 5 ng/ml saliva cotinine to discriminate active tobacco use, there was a 98% concordance between self reported non-use in the past month and cotinine concentration. The sensitivity of the questionnaire compared to the saliva cotinine test, used as the gold standard, was 90% and the specificity 93%. One hundred and fifteen out of 520 subjects (22%) reported monthly tobacco use. Among these, 67% (46/69) of the exclusive cigarette smokers, 82% (23/28) of exclusive snus users, and 94% (15/16) of mixed users (cigarettes + snus) had cotinine concentrations above 5 ng/ml. Among subjects reporting daily use 96% (64/67) had saliva cotinine concentrations above the cut point. Exclusive current cigarette users were more likely to be classified discordantly by questionnaire and cotinine test compared to snus users (odds ratio 3.2, 95% confidence interval 1.2 to 8.6). CONCLUSION: This study confirms the reliability of adolescents' self reported tobacco use. In a context of low exposure to environmental tobacco smoke a cut off for saliva cotinine of 5 ng/ml reliably discriminated tobacco users from non-users. Irregular use of tobacco in this age group probably explains the discrepancy between self reported use and cotinine concentrations.

Effect of garenoxacin on eubacteria in the normal intestinal microflora when administered concomitantly with digoxin.

Garenoxacin is a new des-F(6)-quinolone with a broad antimicrobial spectrum. It has been reported that antibiotics may raise digoxin concentrations in the plasma of patients who are taking these agents concurrently, possibly due to the effect on the digoxin-metabolizing intestinal microflora. Sixteen healthy subjects were given a loading dose of digoxin (0.25 mg orally, q 6 h) on Day 1 followed by once-daily doses of 0.25 mg on Days 2 through 14. The subjects also received garenoxacin 600 mg orally, q 24 h, on Days 8 through 14. The number of enterococci, bacilli, corynebacteria, enterobacteria, bifidobacteria, lactobacilli, clostridia and bacteroides decreased whereas the number of eubacteria increased in the intestinal microflora. Eubacterium lentum strains increased during the administration of garenoxacin and returned towards normal levels within 14 days after the last dose of garenoxacin. The fecal concentrations of garenoxacin varied between 14.0-310.0 mg/kg. The minimum inhibitory concentrations of garenoxacin against the isolated E. lentum strains were >64 mg/L. There was no degradation of digoxin by the E. lentum strains.

Alteration of pharmacokinetics of cyclophosphamide and suppression of the cytochrome p450 genes by ciprofloxacin.

Recently, it has been reported that prophylactic administration of ciprofloxacin during cyclophosphamide (CY) conditioning was a high-risk factor for relapse in patients undergoing allogeneic BMT. In the present study, we investigated the possible mechanisms of this interaction in male Sprague-Dawley rats. The kinetics of CY and its active 4-OH-CY metabolite were determined, after 3 days pretreatment with ciprofloxacin (200 mg/kg) and compared to control rats without treatment. CY was administered as a high or low single intravenous dose (150 and 90 mg/kg, respectively). The expression of the CYP2B1, CYP2B2, CYP2C11, CYP3A1 and CYP3A2 genes was evaluated by SYBR Green I Dye real-time PCR for quantification of mRNA. The administration of ciprofloxacin resulted in a significant increase in the AUC (P=0.007) and a significant decrease in clearance (P=0.007) when CY was given as a high dose. In accordance, the metabolic ratio (AUC4-OH-CY/AUCCY) was significantly lower (P=0.007) compared to that found in the control group. Ciprofloxacin significantly suppressed gene expression of CYP2C11 (P=0.01) and CYP3A1 (P=0.04); however, no effect was observed on the gene expression of CYP3A2, CYP2B1 and CYP2B2. Our study revealed that ciprofloxacin interacts with CY and suppressed relevant cytochromes p450 at the transcriptional level. This study may have a great clinical impact when ciprofloxacin is used in therapy.

Effects of glucocorticoids on leptin levels and eating behaviour in women.

OBJECTIVE: Long-term treatment with glucocorticoids induces weight gain and increased risk to develop obesity-related metabolic complications. The underlying mechanisms are not fully understood. Glucocorticoid therapy has previously been associated with increased levels of circulating leptin. In this study the eating behaviour was therefore studied in relation to leptin levels before and after short-term prednisolone treatment. DESIGN: Within-subject design. SUBJECTS: Twelve healthy postmenopausal women with a mean body mass index (BMI) of 28.9 kg m-2 (+/-0.8 SEM) volunteered after recruitment by an advertisement in the local paper. INTERVENTIONS: The subjects received 25 mg prednisolone daily for 7 days. MAIN OUTCOME MEASUREMENTS: Fasting serum samples were obtained before, during and after treatment for determination of leptin and insulin, glucose and fractionated lipoproteins in plasma. The microstructure of the eating behaviour was registered with a universal eating monitor, VIKTOR. Appetite was estimated by visual analogue rating scales and food intake by a 48-h recall. RESULTS: Serum leptin increased after 2 and 7 days of glucocorticoid administration (P < 0.01), and the food intake measured by VIKTOR after 7 days of treatment (P < 0.05). No statistically significant changes were however, found in the 48-h food- recall or in the subjective appetite registrations. Insulin levels were borderline elevated (P = 0.062) after treatment, but no significant changes of fasting glucose were seen. High density lipoprotein cholesterol (HDL) increased (P < 0.05), whilst low density lipoprotein cholesterol (LDL) decreased (P < 0.05). CONCLUSION: Food intake was elevated after glucocorticoid administration as observed with an objective, quantitative method, in spite of increased levels of circulating leptin.

Inhalation and deposition of nebulized sodium cromoglycate in two different particle size distributions in children with asthma.

The relative deposition of two inhaled droplet size distributions of sodium cromoglycate produced by a Hudson Updraft II nebulizer was evaluated, using a setup modified from the proposed Comité Européen Normalisé (CEN) standard prEN 13544-1. The modified setup comprised an Andersen 296 impactor and a Spira Electro 2 dosimeter. The setup was characterized prior to use in children with sodium cromoglycate (SCG) and sodium fluoride as tracer aerosol. The main in vivo study was designed to allow nine children with a mean age of 10 years to inhale SCG aerosol at two different relative humidities (RH), a high RH (> 90%) and a low RH (13%), which in turn resulted in two different droplet size distributions. The nebulizer/dosimeter was set to provide 1-sec nebulization during 50 inhalations. Throughout the exposures, the children were instructed to inhale in a consistent manner with target tidal volumes (0.5 L) and inhalation flows (0.4 L/sec). Blood samples were taken at predefined time intervals, and the area under the curve (AUC) was calculated. A lung deposition program, TGLD2, was used to calculate the expected deposition, using the droplet sizes and inhalation parameters obtained during in vivo exposures. The in vivo monitoring of droplet size distribution during the exposure showed that the low, intermediate (room air), and high RHs gave a mean droplet size distribution with a mass median aerosol diameter (MMAD) of 1.2, 1.7, and 2.0 microm, respectively. The average tidal volume over all exposures was 0.51 +/- 0.12 L. The total deposition fraction was 33.4% of the estimated nebulizer output. A correlation was found between tidal volume and the calculated deposited fraction. The results indicate that there is a difference in total deposition, depending on the size of the droplet size distribution, with the larger droplet size distribution (MMAD, 2.0 microm) having a higher total deposition than the smaller droplet size distribution (MMAD, 1.2 microm). The deposition results were in good agreement with the deposition fractions estimated using the TGLD2 software for the inhalation parameters found in the study. The obtained study results can arise from differences in regional deposition, but may also be explained by differences in extrathoracic deposition.

Responder characteristics to a single oral dose of cholinesterase inhibitor: a double-blind placebo-controlled study with tacrine in Alzheimer patients.

A proportion of Alzheimer's disease (AD) patients treated for several months with cholinesterase (ChE) inhibitors have shown some favorable response on cognition, but the characteristics of the responders are still unclear. This study attempts to identify the characteristics of individuals with a positive behavioral response after a double-blind randomized administration of a single oral dose of tacrine (40 mg) and placebo to AD patients. Furthermore, the relationship between single-dose and long-term responders are examined. Twenty-four mildly to very mildly demented AD patients participated in the study. They all fulfilled the diagnosis of probable AD according to NINCDS-ADRDA criteria. Active treatment (tacrine 40 mg) and placebo was administered in random order on 2 consecutive days, and the effects were evaluated within 2 h using neuropsychological tests (assessing visuospatial ability, episodic memory and attention), registration of EEG activity and measurement of red blood cells (RBC) acetylcholinesterase (AChE), ChE activity and concentrations of tacrine and its metabolites in plasma. Results demonstrated significant improvement, tacrine compared to placebo, in measures of attention, but not in episodic memory or visuospatial ability. A single-dose response was therefore defined in terms of improvement in attention. The tacrine plasma concentration (pcTHA) showed a positively skewed distribution (mean +/- SD: 10.5 +/- 11.8, range: 1.0-51.8 ng/ml). There were no significant differences between single-dose responders compared to nonresponders in pcTHA, metabolites of tacrine, inhibition of AChE in RBC, tau levels in CSF, AChE activity in CSF or plasma and demographic variables. However, single-dose responders showed a higher right frontal alpha/theta ratio on EEG and had lower glucose metabolism in the parietal-temporal association cortex at baseline. In addition, the frequency of apolipoprotein E (APOE) epsilon 4 alleles was higher in responders. Interestingly, the single-dose response was related to the long-term response, although not significantly, which probably was due to lack of power. To conclude, the present study identified single-dose responders in terms of improved attentional performance associated with a relatively higher alpha/theta activity in the right frontal regions of the brain measured on EEG and predominance of APOE epsilon 4 allele.

Preparation of sulfhydrylborane-dextran conjugates for boron neutron capture therapy.

This study presents a carrier system for boron, potentially useful in boron neutron capture therapy (BNCT). Na2B12H11SH (BSH) was covalently coupled to dextran derivatives. This was accomplished in two ways. The first method comprises activation of dextran with 1-cyano-4-(dimethylamino)pyridine (CDAP) with subsequent coupling of 2-aminoethyl pyridyl disulfide (method A). The thiolated dextran could then couple BSH in a disulfide exchange reaction. In the second procedure, dextran was derivatized to a multially derivative (method B) which reacted with BSH in a free-radical-initiated addition reaction. The assessment of boron content of the conjugates was done by elemental analysis of sulfur and atomic spectroscopy of boron (ICP-AES). With method A, only limited numbers of boron cages could be coupled (10-20 cages per dextran chain). With method B, 100-125 boron cages per dextran chain was obtained, corresponding to 1200-1500 boron atoms per dextran chain. This result makes this derivative a promising template for use in the development of BNCT agents.

Clinical adsorption and photodegradation of the fatsoluble vitamins A and E.

The adsorption of the fat-soluble vitamins A and E to administration sets and their photodegradation was studied under varying conditions. Infusion bottles with or without photoprotectors (red plastic bags) were studied, as were systems exposed to the blue light, used in the treatment of hyperbilirubinaemia, which has a maximum emission spectrum at 450 nm. An IV bag containing lipids, carbohydrates, amino-acids, minerals and vitamins was also studied. Vitamin levels in all administration sets decreased by approximately 30% during the first 3h, except for those in the IV bag. Vitamins were best preserved in the IV bag, where 85-90% of both vitamins remained after 20h. Vitamin E appeared to suffer from both adsorption and photodegradation but to a lesser extent than vitamin A. Vitamin A displayed a greater tendency for adsorption. In order to avoid loss of vitamins during parenteral administration, we recommend that they should be administered as a bolus or during a limited period of 1 h, and that the system be protected from light.

Direct solid-phase time-resolved immunofluorometric assay of cortisol in serum.

A dissociation-enhanced lanthanide fluoroimmunoassay of serum cortisol based on time-resolved fluorescence is described. The assay is a direct assay, where cortisol immobilized on the wall of a microtiter-strip well competes with cortisol in the sample for the europium-labeled polyclonal antibody. The amount of bound europium-labeled antibody is inversely proportional to the amount of cortisol in the sample. Separation is accomplished by washing the strip well. The assay is carried out in 2 h, at room temperature; it is easy to perform and gives accurate and reliable results. A chaotropic agent, trichloracetic acid, was very effective in releasing cortisol from binding proteins. This finding will have practical importance in the immunoassay field.

The measurement of serum cortisol by a solid-phase chemiluminescence immunoassay.

A solid-phase chemiluminescent immunoassay (LIA) for the determination of cortisol in serum specimens has been developed. The separation of the cortisol onto the solid-phase distinguishes this particular assay from other chemiluminescence immunoassays. The method can be used without prior extraction. Cortisol molecules were made chemiluminescent by conjugation to aminobutylethyl-isoluminol. The detection limit of the label in the chemiluminescent reaction was 0.1 pmol. The LIA was compared with a RIA for cortisol in 36 serum specimens and the correlation between the assays was good (r = 0.97). The time course of the chemiluminescent reaction is fast and a 20's integration time gave reproducible results. The peak light intensities were not reliable.