The air temperature change effect on water quality in the Kvarken Archipelago area

The Kvarken Archipelago is Finland's World Heritage site designated by UNESCO. How climate change has affected the Kvaken Archipelago remains unclear. This study was conducted to investigate this issue by analyzing air temperature and water quality in this area. Here we use long-term historical data sets of 61 years from several monitoring stations. Water quality parameters included chlorophyll-a; total phosphorus; total nitrogen; coliform bacteria thermos tolerant; temperature; nitrate as nitrogen; nitrite-nitrate as nitrogen, and Secchi depth and correlations analysis was conducted to identify the most relevant parameters. Based on the correlation analysis of weather data and water quality parameters, air temperature showed a significant correlation with water temperature (Pearson's correlations = 0.89691, P < 0.0001). The air temperature increased in April (R² (goodness-of-fit) = 0.2109 &P = 0.0009) and July (R² = 0.1207 &P = 0.0155) which has indirectly increased the chlorophyll-a level (e.g. in June increasing slope = 0.39101, R² = 0.4685, P < 0.0001) an indicator of phytoplankton growth and abundance in the water systems. The study concludes that there might be indirect effects of the likely increase in air temperature on water quality in the Kvarken Archipelago, in particular causing water temperature and chlorophyll-a concentration to increase at least in some months.

Shell-structure and pairing interaction in superheavy nuclei: rotational properties of the z=104 nucleus (256)rf

The rotational band structure of the Z=104 nucleus (256)Rf has been observed up to a tentative spin of 20ℏ using state-of-the-art γ-ray spectroscopic techniques. This represents the first such measurement in a superheavy nucleus whose stability is entirely derived from the shell-correction energy. The observed rotational properties are compared to those of neighboring nuclei and it is shown that the kinematic and dynamic moments of inertia are sensitive to the underlying single-particle shell structure and the specific location of high-j orbitals. The moments of inertia therefore provide a sensitive test of shell structure and pairing in superheavy nuclei which is essential to ensure the validity of contemporary nuclear models in this mass region. The data obtained show that there is no deformed shell gap at Z=104, which is predicted in a number of current self-consistent mean-field models.

An evaluation of the feasibility, cost and value of information of a multicentre randomised controlled trial of intravenous immunoglobulin for sepsis (severe sepsis and septic shock): incorporating a systematic review, meta-analysis and value of information analysis

BACKGROUND

Sepsis is a syndrome characterised by a systemic inflammatory response to infection that leads to rapid acute organ failure and potentially rapid decline to death. Intravenous immunoglobulin (IVIG), a blood product derived from human donor blood, has been proposed as an adjuvant therapy for sepsis.

OBJECTIVES

To describe current practice in the management of adult patients severely ill with sepsis (severe sepsis or septic shock) in the UK; to assess the clinical effectiveness of IVIG for severe sepsis and septic shock and to obtain the appropriate inputs for the relative efficacy parameters, and the key uncertainties associated with these parameters, required to populate the decision model; to develop a decision-analytic model structure and identify key parameter inputs consistent with the decision problem and relevant to an NHS setting; and to populate the decision model and determine the cost-effectiveness of IVIG and to estimate the value of additional primary research.

DATA SOURCES

Existing literature on IVIG and severe sepsis. Existing case-mix and outcome data on critical care admissions. Survey data on management of admissions with severe sepsis. Databases searched for clinical effectiveness were Cochrane Infectious Diseases Group Specialized Trials Register, the Cochrane Trials Register, MEDLINE and EMBASE. Dates searched were 1 January 2002 to 2 October 2009 to update previous Cochrane review. Databases searched for cost-effectiveness were NHS Economic Evaluation Database (NHS EED) to 2 October 2009, MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations and EMBASE to 20 October 2009.

REVIEW METHODS

Systematic literature searching with data extraction, descriptive analysis and clinical effectiveness and cost-effectiveness modelling of IVIG in severe sepsis. Additional primary data analysis. Expected value of information (EVI) analysis.

RESULTS

Our meta-analysis, the first to simultaneously allow for type of IVIG (IVIG or immunoglobulin M-enriched polyclonal IVIG), choice of control (no treatment or albumin), study quality/publication bias and other potential covariates, indicated that the treatment effect of IVIG on mortality for patients with severe sepsis is borderline significant with a large degree of heterogeneity in treatment effect between individual studies. Modelling indicated that there were issues with bias associated with trial methodology, publication and small-study effects with the current evidence. The large degree of heterogeneity in treatment effects between studies, however, could be explained (best-fitting model) by a measure of study quality (i.e. use of albumin as control - as an indicator of proper blinding to treatment as a proxy for study quality - associated with decreased effect) and duration of IVIG therapy (longer duration associated with increased effect). In-depth discussion within the Expert Group on duration of IVIG therapy, with daily dose and total dose also clearly inter-related, indicated no clear clinical rationale for this association and exposed a lack of evidence on the understanding of the mechanism of action of IVIG in severe sepsis. Although the EVI analyses suggested substantial expected net benefit from a large, multicentre randomised controlled trial (RCT) evaluating the clinical effectiveness of IVIG, the remaining uncertainties around the design of such a study mean that we are unable to recommend it at this time.

LIMITATIONS

As has been identified in previous meta-analyses, there are issues with the methodological quality of the available evidence.

CONCLUSIONS

Although the results highlight the value for money obtained in conducting further primary research in this area, the biggest limitation for such research regards the uncertainties over the mechanism of action of IVIG and the heterogeneous nature of severe sepsis. Resolving these would allow for better definition of the plausibility of the effectiveness scenarios presented and, consequently, a better understanding of the cost-effectiveness of this treatment. This information would also inform the design of future, primary evaluative research. Our recommendations for future research focus on filling the knowledge gaps to inform a future multicentre RCT prior to recommending its immediate design and conduct.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Capecitabine for the treatment of advanced gastric cancer

This paper presents a summary of the evidence review group (ERG) report into capecitabine for advanced gastric cancer (aGC). Capecitabine is an oral prodrug of 5-fluorouracil (5-FU). The decision problem addressed was the use of capecitabine (X) compared to 5-FU (F), in combination regimens with platinum agents [cisplatin (C) or oxaliplatin (O)] with or without epirubicin (E), in patients with inoperable aGC. Approximately 7000 new cases of gastric cancer are diagnosed in England and Wales every year. Of these, 80% are candidates for palliative chemotherapy and around 2900 receive such treatment. The standard UK practice for patients with aGC who are considered fit enough has consisted of a triplet regimen comprising intravenous 5-FU in combination with a platinum agent (capecitabine or oxaliplatin) and epirubicin. The manufacturer's submission (MS) focused on direct evidence from two phase III non-inferiority randomised controlled trials (RCTs), REAL-2 (Randomized ECF for Advanced and Locally advanced oesophagogastric cancer-2; n = 1002) and ML17032 (n = 316). REAL-2 randomised patients to four regimens (ECF, ECX, EOF and EOX) to compare 5-FU with capecitabine and cisplatin with oxaliplatin, whereas ML17032 compared CX with CF. Efficacy outcomes from these trials were pooled in an individual patient data (IPD) meta-analysis. Both RCTs demonstrated statistically significant non-inferiority of capecitabine on the outcome of overall survival (OS) assessed in the per-protocol population; equivalent results were also demonstrated for progression-free survival (PFS). The IPD meta-analysis found a statistically significant benefit in OS for capecitabine compared with 5-FU [unadjusted hazard ratio (HR): 0.87; 95% confidence interval (CI) 0.77 to 0.98, p = 0.027]. There was no evidence of a poorer safety profile for capecitabine overall, nor of any difference in quality of life (QoL) between the two fluoropyrimidines. The MS included a de novo economic evaluation based on a cost-minimisation analysis (CMA), where the costs of capecitabine-based regimens were compared with their equivalent 5-FU-based regimens in aGC. A time horizon of 5.5 cycles (each lasting for 21 days) was used in the base-case analysis, representing the duration of treatment. The results of the manufacturer's base-case analysis showed that capecitabine regimens are associated with mean net cost savings of 1620 pounds (ECX vs ECF), 1572 pounds (EOX vs EOF) and 4210 pounds (CX vs CF). The manufacturer failed to comment explicitly on the uncertainty around the estimates of efficacy and on the fact that the IPD meta-analysis suggests that capecitabine may actually be more effective on average. Further analyses exploring additional costs incurred by the UK NHS from extending survival duration showed that these are unlikely to have a material effect on conclusions. A full probabilistic analysis was not performed; however, the evidence explored by the MS and ERG is consistent in suggesting that capecitabine has a lower mean cost than 5-FU-based regimens. The submission was considered to contain convincing evidence of the non-inferiority of capecitabine to 5-FU on survival; this evidence was considered to be applicable to UK practice. Although some uncertainty remains, the ERG deemed CMA to be an appropriate framework with which to analyse this decision problem. Overall cost estimates for the CMA were generated appropriately and were robust to uncertainties regarding assumptions and sources. At the time of writing, the guidance document issued by NICE on 28 July 2010 states that capecitabine in combination with a platinum-based regimen is recommended for the first-line treatment of inoperable advanced gastric cancer.

Capecitabine for the treatment of advanced gastric cancer

This paper presents a summary of the evidence review group (ERG) report into capecitabine for advanced gastric cancer (aGC). Capecitabine is an oral prodrug of 5-fluorouracil (5-FU). The decision problem addressed was the use of capecitabine (X) compared to 5-FU (F), in combination regimens with platinum agents [cisplatin (C) or oxaliplatin (O)] with or without epirubicin (E), in patients with inoperable aGC. Approximately 7000 new cases of gastric cancer are diagnosed in England and Wales every year. Of these, 80% are candidates for palliative chemotherapy and around 2900 receive such treatment. The standard UK practice for patients with aGC who are considered fit enough has consisted of a triplet regimen comprising intravenous 5-FU in combination with a platinum agent (capecitabine or oxaliplatin) and epirubicin. The manufacturer’s submission (MS) focused on direct evidence from two phase III non-inferiority randomised controlled trials (RCTs), REAL-2 (Randomized ECF for Advanced and Locally advanced oesophagogastric cancer-2; n = 1002) and ML17032 (n = 316). REAL-2 randomised patients to four regimens (ECF, ECX, EOF and EOX) to compare 5-FU with capecitabine and cisplatin with oxaliplatin, whereas ML17032 compared CX with CF. Efficacy outcomes from these trials were pooled in an individual patient data (IPD) meta-analysis. Both RCTs demonstrated statistically significant non-inferiority of capecitabine on the outcome of overall survival (OS) assessed in the per-protocol population; equivalent results were also demonstrated for progression-free survival (PFS). The IPD meta-analysis found a statistically significant benefit in OS for capecitabine compared with 5-FU [unadjusted hazard ratio (HR): 0.87; 95% confidence interval (CI) 0.77 to 0.98, p = 0.027]. There was no evidence of a poorer safety profile for capecitabine overall, nor of any difference in quality of life (QoL) between the two fluoropyrimidines. The MS included a de novo economic evaluation based on a cost-minimisation analysis (CMA), where the costs of capecitabine-based regimens were compared with their equivalent 5-FU-based regimens in aGC. A time horizon of 5.5 cycles (each lasting for 21 days) was used in the base-case analysis, representing the duration of treatment. The results of the manufacturer’s base-case analysis showed that capecitabine regimens are associated with mean net cost savings of £1620 (ECX vs ECF), £1572 (EOX vs EOF) and £4210 (CX vs CF). The manufacturer failed to comment explicitly on the uncertainty around the estimates of efficacy and on the fact that the IPD meta-analysis suggests that capecitabine may actually be more effective on average. Further analyses exploring additional costs incurred by the UK NHS from extending survival duration showed that these are unlikely to have a material effect on conclusions. A full probabilistic analysis was not performed; however, the evidence explored by the MS and ERG is consistent in suggesting that capecitabine has a lower mean cost than 5-FU-based regimens. The submission was considered to contain convincing evidence of the non-inferiority of capecitabine to 5-FU on survival; this evidence was considered to be applicable to UK practice. Although some uncertainty remains, the ERG deemed CMA to be an appropriate framework with which to analyse this decision problem. Overall cost estimates for the CMA were generated appropriately and were robust to uncertainties regarding assumptions and sources. At the time of writing, the guidance document issued by NICE on 28 July 2010 states that capecitabine in combination with a platinum-based regimen is recommended for the first-line treatment of inoperable advanced gastric cancer.

The effect of rf pulse pattern on bremsstrahlung and ion current time evolution of an ECRIS

Time-resolved helium ion production and bremsstrahlung emission from JYFL 14 GHz ECRIS is presented with different radio frequency pulse lengths. rf on times are varied from 5 to 50 ms and rf off times from 10 to 1000 ms between different measurement sets. It is observed that the plasma breakdown occurs a few milliseconds after launching the rf power into the plasma chamber, and in the beginning of the rf pulses a preglow transient is seen. During this transient the ion beam currents are increased by several factors compared to a steady state situation. By adjusting the rf pulse separation the maximum ion beam currents can be maintained during the so-called preglow regime while the amount of bremsstrahlung radiation is significantly decreased.

Gamma-ray spectroscopy at the limits: first observation of rotational bands in 255Lr

The rotational band structure of 255Lr has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, 255Lr is the heaviest nucleus to be studied in this manner. One rotational band has been unambiguously observed and strong evidence for a second rotational structure was found. The structures are tentatively assigned to be based on the 1/2-[521] and 7/2-[514] Nilsson states, consistent with assignments from recently obtained alpha decay data. The experimental rotational band dynamic moment of inertia is used to test self-consistent mean-field calculations using the Skyrme SLy4 interaction and a density-dependent pairing force.

Fatty acids and ultrastructure of ozone-exposed Aleppo pine (Pinus halepensis Mill.) needles

Fifteen or 18-month-old Aleppo pine seedlings were fumigated with different concentrations and doses of ozone over a period of 2-16 days in controlled-environmental growth chambers. The total fatty acid content and ultrastructure of the current year needles were subsequently analysed. In acute, high concentration exposures, significant reductions in the levels of linolenic acid were detected. Increases in myristic or palmitic acid were common in needles exposed to lower concentrations of ozone. Ultrastructural studies revealed reductions in chloroplast size and a darkening of stroma at low ozone exposures while at high concentrations disruption of the chloroplast membranes was also identified.

The effect of prostatic capsule perforation on the absorption of irrigating fluid during transurethral resection

Thirty patients undergoing transurethral resection of the prostate using ethanol-tagged irrigating fluid were investigated in order to study the effects of a breach in the prostatic capsule. Measurements were made of end-tidal ethanol (ET-ethanol) in the expired air, serum glycine and sodium, haemoglobin, blood loss and volumetric determination of irrigating fluid absorption. Perforation of the prostatic capsule occurred in 13 patients (Group P), with 17 judged to have no perforation (Group NP). In all Group NP patients the ET-ethanol remained below 0.05/1000, serum sodium decreased by < or = 3 mmol/l and serum glycine remained < 1.5 mmol/l. ET-ethanol was significantly increased in Group P, rising to between 0.1 and 0.45/1000 in 5 patients, 3 of whom showed a reduction in serum sodium > 5 mmol/l. Five patients in Group P demonstrated significantly raised serum glycine concentrations up to 15 mmol/l. These findings suggest that perforation of the prostatic capsule may lead to rapid absorption of irrigating fluid, and that ET-ethanol monitoring is a useful method of detecting this quickly.

Synthesis and analysis of O,O'-dicarboxylate (dibenzyl) bispilocarpates as possible prodrugs of pilocarpine

As a part of a series of studies to develop prodrug derivatives of pilocarpine, the O,O'-succinyl (dibenzyl), O,O-adipoyl (dibenzyl), O,O-fumaryl (dibenzyl), and O,O-terephthaloyl (dibenzyl) bispilocarpate fumarates were synthesized as a new class of pilocarpine prodrugs. The compounds were prepared from pilocarpic acid benzyl monoester by coupling two pilocarpic acid benzyl monoesters together with spacer chains by usual esterification methods. Liquid chromatography, thermospray liquid chromatography-mass spectrometry, high-resolution mass spectrometry, and NMR spectroscopy were applied to the identification and the purity evaluation of the synthetic products.

Improved corneal pilocarpine permeability with O,O'-(1,4-xylylene) bispilocarpic acid ester double prodrugs

O,O'-(1,4-Xylylene) bispilocarpic acid esters are pilocarpine prodrugs containing two pilocarpic acid monoesters linked with one pro-moiety. Each mole of prodrug forms two pilocarpine moles in the presence of esterases. Corneal uptake and permeability of various bispilocarpic acid diesters were investigated in vitro using isolated albino rabbit corneas. The permeability coefficient of pilocarpine was 2.8 x 10(-6) cm/sec, whereas for bispilocarpic acid diesters, despite their large molecular weights (between 638 and 722), permeability coefficients were 6.5-20.2 x 10(-6) cm/sec. Only pilocarpine, and no intact prodrug, was observed at the endothelial side. Corneal uptake was increased with increasing lipophilicity, but a parabolic relationship between the logarithm of the apparent partition coefficient (1-octanol-pH 7.4 phosphate buffer) (log PC) and the corneal permeability was noticed. Corneal permeability and the rate of enzymatic hydrolysis of the compounds correlated well. The corneal permeability of pilocarpine given as lipophilic bispilocarpic acid diester (log PC greater than or equal to 3) prodrugs seems to be controlled by the formation of pilocarpine in the corneal epithelium rather than by the absorption of prodrugs into the epithelium or their epithelium-stroma transport rate.

Relative pharmacokinetics of three oral 400 mg ibuprofen dosage forms in healthy volunteers

The pharmacokinetic properties of two solid form, 400 mg ibuprofen (IP) preparations, a soft gelatin capsule and a film-coated tablet, were compared to those obtained after the administration of liquid prepared from effervescent IP tablets. IP was absorbed rapidly (tmax 0.6-1.9 h). The fastest absorption was observed after the ingestion of the soft gelatin capsule; liquid and film-coated tablet produced 12.2-7.8 times longer absorption half-lives, 50-39% lower peak concentrations of IP in serum and 3.5-3.2 times higher tmax values. Bioavailabilities were close to similar after all products. All products were tolerated without side effects in this single-dose, crossover study on 14 healthy volunteers. The results of this study support the earlier findings that after oral administration, IP is absorbed equally well from solid formulations as from liquid form. Liquid formulations of IP often deliver slower absorption than expected probably due to incomplete dissolution of the active principle. This may have therapeutic significance, and it should be taken into account when studies on the relative bioavailability of IP from pharmaceutical drug products are planned.

Synthesis and identification of pilocarpic acid diesters, prodrugs of pilocarpine

A series of new pilocarpic acid diesters were synthesized to obtain prodrugs for pilocarpine with varying physico-chemical properties. Thermospray liquid chromatography-mass spectrometry (TSP-LC-MS), liquid chromatography with UV-detection (LC-UV) and NMR-spectroscopy were used for the identification of the synthetic products and for evaluation of their purity including typical impurities (pilocarpic acid monoester, pilocarpine). TSP-LC-MS-analysis was performed in the reversed-phase mode using acetonitrile (60%)-0.2 M ammonium acetate (40%) as mobile phase. In LC-UV-analysis chromatographic separation was carried out on a reversed-phase column and the mobile phase consisted of methanol (71%) and 0.02 M potassium dihydrogen phosphate, pH 4.5 (29%). Electron ionization-mass spectrometry (EI-MS) was used for elucidation of structures. Elemental compositions of the substances were verified with high resolution-mass spectrometry (HR-MS). The complete establishment of structures presented was based on 1H-, and COSY-NMR-spectroscopy joined to TSP-LC-MS-analysis.

Determination of physicochemical properties, stability in aqueous solutions and serum hydrolysis of pilocarpic acid diesters

New alkyl and aralkyl pilocarpic acid diesters, prodrugs of pilocarpine, were synthesized with the aim of improving the bioavailability of pilocarpine by increasing its corneal permeability. These esters were several orders of magnitude more lipophilic than pilocarpine as determined by their apparent partition coefficients between 1-octanol and phosphate buffer (pH 7.40) (log P). Good correlation between log P and HPLC capacity factors of the compounds was observed. All the compounds are stable in acidic aqueous solution; in serum, however, pilocarpic acid diesters are hydrolysed enzymatically to pilocarpic acid monoester, which undergoes spontaneous cyclization to active pilocarpine and inactive isopilocarpine. The half-lives of the diesters in serum varied from 6-232 min. In addition to the direct effects of the R2, R1 moiety had a remarkable effect on the rate of enzyme-catalysed hydrolysis taking place in moiety R2. The formed pilocarpine was analysed with a new HPLC method which allowed good resolution of pilocarpine, isopilocarpine, pilocarpic acid and isopilocarpic acid. Rates for pilocarpine formation were both determined by experiment and calculated using the STELLA simulation programme with known degradation rate constants of pilocarpic acid diesters and monoesters. Since the simulations were in good agreement with the experimental results, it is concluded that STELLA simulation programme is useful in predicting pilocarpine formation.

Bioavailability of doxycycline from dissolved doxycycline hydrochloride tablets--comparison to solid form hydrochloride tablets and dissolved monohydrate tablets

Doxycycline (DC) is used either as solid form hydrochloride capsules, or as monohydrate tablets, which may be taken either as solid form tablets or dissolved in water. In this single dose (150 mg), crossover study on 15 healthy volunteers, the pharmacokinetic properties of DC from hydrochloride tablets taken either in dissolved or in solid form were compared with those observed after taking dissolved DC as a monohydrate tablet. The results of this study show that DC is absorbed rapidly (tmax 3.3-3.8 h) and with equal bioavailability (AUC values 52.9-58.5 mg/l x h) from both hydrochloride and monohydrate tablets. It can be concluded that taking the DC hydrochloride tablets in dissolved form does not affect the pharmacokinetics of DC, moreover the bioavailability of DC is comparable to that achieved after taking DC monohydrate tablets in dissolved form.

Pharmacokinetics of ibuprofen in man: a single-dose comparison of two over-the-counter, 200 mg preparations

The pharmacokinetic properties of two 200 mg, over-the-counter (OTC) ibuprofen preparations were compared in a randomized crossover study on ten healthy volunteers. After 2 times 200 mg single dose, one preparation produced peak plasma ibuprofen concentration 30.0 +/- 2.1 micrograms/ml at 1.6 h and the other preparation 23.2 +/- 1.9 micrograms/ml at 2.3 h (p less than 0.05). There was no statistically significant difference between the preparations in the bioavailability of ibuprofen. OTC ibuprofen preparations are mainly used for acute indications, such as fever or headache. In these cases, rapid absorption and high concentrations of active ingredient are desirable properties, especially when the amount of drug is relatively low. Therefore, the pharmacokinetic differences between these preparations may be therapeutically significant.

Specific and sensitive quantitation of medroxyprogesterone acetate in human serum by gas chromatography-mass spectrometry

A procedure for the quantitation of medroxyprogesterone acetate in serum using gas chromatography-quadrupole mass spectrometry is described. Medroxyprogesterone propionate, synthesized from medroxyprogesterone, was used as the internal standard. The serum samples were extracted on Bond Elut C18 cartridges, and the acetate and propionate were determined as their 3-enol heptafluorobutyrate esters by selected-ion monitoring technique. The linear range of the standard curve in serum was 0.5-30 ng/ml with a lower limit of quantitation of 0.5 ng/ml. The coefficient of variation of the method was 3.1% at 10 ng/ml and 5.5% at 1 ng/ml. The method is very rapid, and it has been applied for routine measurements of medroxyprogesterone acetate levels in human serum after oral administration of 10 or 20 mg.

Stimulation by oestradiol of the urinary excretion of perfluorooctanoic acid in the male rat

The urinary excretion of perfluorooctanoic acid (PFOA) was studied in male Wistar rats after castration and oestradiol administration as well as in intact females and males. During the first 24 hr females excreted 72 +/- 5% (N = 6) of a single intraperitoneal dose of PFOA (50 mg/kg) in urine whereas the intact males excreted only 9 +/- 4% (N = 6). After castration followed by oestradiol administration (500 micrograms/kg every 2nd day for 14 days), the males excreted PFOA in urine in similar amounts as the females (68 +/- 14% at 24 hr, N = 10). Oestradiol treatment of non-castrated males produced similar results (61 +/- 19% at 24 hr, N = 10). Also castration without oestradiol administration significantly enhanced the renal PFOA excretion, but not as effectively as oestradiol treatment. After 96 hr, the concentration of PFOA in serum of intact males was 17-40 times higher than in the serum of other groups. PFOA was similarly bound by the proteins in the serum of females and males. Phase II metabolism of PFOA was not shown either in males or females.

Concentrations of tryptoline and methtryptoline in rat brain

Combined gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry have been used to identify and quantify tryptoline, methtryptoline, 5-hydroxytryptoline, and 5-hydroxymethtryptoline as their heptafluorobutyryl derivatives in extracts of rat brain. Tryptoline and methtryptoline were identified on the basis of their retention times and mass spectral characteristics: they were reliably detected in brain tissue extracts without interference from artifactual formation; their whole brain concentrations ranged between 0.2 and 3 ng/g; and they had a similar neuroanatomical distribution, with the highest concentrations in the cerebellum and the cortex. Smaller quantities of 5-hydroxytryptoline and 5-hydroxymethtryptoline were also identified on the basis of their retention times and mass spectral characteristics. However, the significance of this finding is unclear, because these two compounds were accompanied by larger quantities of their tetradeuterated analogues formed from tetradeuterated-5-hydroxytryptamine added at the time of tissue homogenization; this result suggests that formation of 5-hydroxytryptoline and 5-hydroxymethtryptoline occurred during tissue homogenization, sample preparation, or both.

Determination of tryptamine in rat brain by gas chromatography—mass spectrometry

Tryptamine (TA) occurs in trace levels in the brain, but its role in the central nervous system is not clear. However, there is evidence that TA may be a neuromodulator since it binds to specific binding sites in the brain. TA was measured as a diheptafluorobutyryl derivative in rat whole brain by capillary gas chromatography-mass spectrometry using negative chemical ionization (NCI) and single ion monitoring (SIM). d(4)-TA was used as the internal standard. The ions m/z 532 and m/z 536 were monitored to identify TA and d(4)-TA, respectively and to calculate the concentration of TA in rat whole brain which was found to be 0.19 +/- 0.08 ng g(-1) (n = 8). The results confirm the earlier TA concentrations measured by GC-MS using positive electron impact ionization. However, NCI improved the signal/noise ratio of the method increasing its sensitivity for TA.

Decarboxylation of 1,2,3,4-tetrahydro-beta-carboline-1-carboxylic acids in brain homogenate and catalysis by pyridoxal-5'-phosphate

[Carboxyl-14C] labelled 1,2,3,4-tetrahydro-beta-carboline-1-carboxylic acid (I) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-1-carboxylic acid (II) were synthesized and their decarboxylation was studied in mouse brain homogenate and buffer. The decarboxylation rates of (I) and (II) in the homogenate were about 6-fold and 4-fold, respectively, as compared with the rates in phosphate buffer. The increase could not be prevented by preheating the homogenate, but was partially abolished by addition of 1 mM EDTA. The decarboxylation was increased dose-dependently when pyridoxal-5'-phosphate was included in the buffer, 400 microM being sufficient to exceed the rate in homogenate for both (I) and (II). Mass spectrometric examination of the decarboxylation products indicated that both (I) and (II) were degraded mainly to corresponding 1,2,3,4-tetrahydro-beta-carbolines, but some 3,4-dihydro analogues also were detectable. In conclusion, the results outline a way through which these pharmacologically active beta-carbolines are readily formed under conditions that may be regarded as physiological.

Toxicity of Iceland lichen and reindeer lichen

Iceland lichen (Cetraria islandica) is sold in health food stores to prevent various disorders. In olden times it and sometimes also reindeer lichen (Cladonia sp.) have been used as emergency food. Lichen contains bitter and potentially toxic lichen acids and it also concentrates heavy metals. Therefore lichen toxicity was studied with traditional pretreatment methods (boiling, ash-soaking or both). Untreated and only shortly boiled lichens were lethally toxic to mice in 50 and 25% w/w mixtures in food, but when ash-soaking was added mice tolerated Cetraria (but not Cladonia) reasonably well for 3 weeks. In a 3 month test in rats 25% mixture of Cladonia was tolerated well and blood tests were normal at the end. However, urinary protein was increased, the autopsies revealed kidney changes corresponding to a mild heavy metal poisoning, as the lead concentrations in kidney and lichen were high.

The effect of ethanol on the release of free fatty acids from the brain in vivo; a study with push-pull cannula

The release of nonesterified fatty acids (NEFA) in vivo from the brain after a single dose of ethanol (3 g/kg) in naive rats was studied. A guide cannula was implanted stereotaxically above the striatum. After one week the striatum of the freely moving rat was superfused through a push-pull cannula with artificial CSF. One hour samples were collected. The concentrations of NEFA were measured by GC in four samples, one before and three after ethanol or water was given by gavage. Preliminary results suggest that the concentrations of palmitate and stearate in superfusate decrease after ethanol administration. Of the unsaturated NEFA only oleic and linoleic acids were found in the superfusion fluid even then only in trace amounts and with no major change after ethanol. It remains to be studied whether the reduced outflow of saturated NEFA is related to the increased rigidity of membranes.

Distribution of 1,2,3,4-tetrahydro-beta-carboline and 6-methoxy-1,2,3,4-tetrahydro-beta-carboline in mice

The distribution of radioactivity after intravenous injection of 14C-labelled 1,2,3,4-tetrahydro-beta-carboline (THBC) and 6-methoxy-1,2,3,4-tetrahydro-beta-carboline (6-MeO-THBC) was studied on mice by whole-body autoradiography and by liquid scintillation counting (LSC). Following intravenous injection they rapidly distributed into different organs and were excreted into urine and the gut contents. A considerable uptake of the compounds was seen in the lungs, kidney, liver, bone marrow, urinary bladder, gastrointestinal tract and in various glands e.g. adrenal, Harderian and salivary glands. THBC moderately penetrated the blood-brain barrier and the placenta but 6-MeO-THBC seemed to penetrate poorly both. At early stages of the experiment the values of tissue radioactivity in LSC were generally much higher in the THBC group but 24 hours following injections the reverse was true with higher activities in the 6-MeO-THBC group. The initial excretion of 6-MeO-THBC seemed to be more rapid judged by the superfluous accumulation of activity in the bladder and a high accumulation of activity into the gut contents.

Tetrahydro-beta-carbolines: effect on alcohol intake in rats

Some beta-carbolines, such as tetrahydro-beta-carboline (THBC) and 6-methoxy-THBC, occur normally in mammalian tissues, and 1-methyl-THBC has been found in human blood after alcohol intake. Continuous intraventricular (ICV) infusion of THBC and 1-methyl-THBC for 14 days was shown to increase voluntary alcohol intake in rats during the second week of infusion. In this study the experimental arrangement was slightly modified. Alcohol was offered for 7 days before the start of the 14 days of ICV infusion with Alzet minipumps and alcohol concentration (3-30% v/v) was increased every second day. The rats consumed less alcohol in the second day with the same concentration. Also, the dose of 47 nmoles/hr of 1-Me-THBC increased the voluntary alcohol intake over the controls, but only during the last 7 days. The same dose of 6-MeO-THBC, a serotonergic beta-carboline, was ineffective. Neither drug changed the total fluid intake. This study suggests that the increased voluntary alcohol intake by THBC's is not due to their serotonergic effect. A hypothesis concerning a possible involvement of opiate receptors is presented.

Increased fluidity of a model membrane caused by tetrahydro-beta-carbolines

Alterations in membrane fluidity caused by alcohols and tetrahydro-beta-carbolines (THBCs) have been studied. Dipalmitoylphosphatidylcholine vesicles were used as a membrane preparation, and changes in the fluidity were revealed by two fluorescent probes: 1-anilinonaphthalene-8-sulfonic acid (1,8-ANS) and N-phenylnaphthylamine (NPN). It was found that THBCs, which are condensation products of tryptamine and formaldehyde or acetaldehyde, were at least 2 orders of magnitude more potent in causing fluidity changes than the comparable alcohols (methanol and ethanol). Both 1,8-ANS (binding close to the polar end of the phospholipid molecules) and NPN (binding to the hydrophobic region of the membrane) were able to reveal changes in membrane fluidity, although there were differences between the behavior of the two probes. The condensation product of acetaldehyde--the primary metabolite of ethanol--and tryptamine were found to be 200-300 times more potent in causing fluidity changes than ethanol itself (as determined with both 1,8-ANS and NPN).

Alcohol drinking in the rat: increases following intracerebroventricular treatment with tetrahydro-beta-carbolines

Voluntary alcohol intake has been reported to increase in rats after the repeated intracerebroventricular (ICV) administration of 1,2,3,4-tetrahydro-beta-carboline (THBC) and some tetrahydroisoquinolines, although negative results have also been reported. THBC is a normal constituent in human plasma and platelets; 1-methyl-1,2,3,4-tetrahydro-beta-carboline (1-Me-THBC), however, occurs in the blood after a person drinks alcohol. We have evaluated the effects of two doses of THBC and 1-Me-THBC on voluntary alcohol consumption in rats. ICV infusions were given with Alzet minipumps for 14 days rather than giving repeated ICV injections. Stability of the drugs in the pump was verified using mass spectrometry. On each day the rats chose between water, alcohol (increasing concentrations from 3 to 30%) and an empty bottle. Alcohol intake increased by about 100% (p less than 0.05) during the last six days when 47 nmoles/hr of either THBC or 1-Me-THBC was infused. At the end of the experiment elevated blood concentrations of alcohol (0.02-0.78(0)/00) were found in rats belonging to the THBC or 1-Me-THBC groups and drinking 30% alcohol. The infusion of 0.47 nmoles/hr of either drug did not increase alcohol intake as compared to control.

Identification by selective ion monitoring of 1-methyl-1,2,3,4-tetrahydro-beta-carboline in human platelets and plasma after ethanol intake

1-Methyl-1,2,3,4-tetrahydro-beta-carboline (tetrahydroharman) has been quantified in human platelets and plasma following acute intake of ethanol using a selective ion monitoring method. It was not possible to detect this compound before ethanol intake.

Quantitative gas chromatographic mass spectrometric determination of 1,2,3,4-tetrahydro-beta-carboline in human plasma and platelets

A sensitive and specific method is described for the determination of 1,2,3,4-tetrahydro-beta-carboline in human plasma, based on selected ion monitoring gas chromatography mass spectrometry and employing a deuterium analogue as internal standard. The identification of 1,2,3,4-tetrahydro-beta-carboline is based on monitoring ions m/z 143, 171, 199 and 368 for the heptafluorobutyryl derivative of 1,2,3,4-tetrahydro-beta-carboline or the normal mass spectrum. For quantitation the ratio of ions m/z 368/370 was used. The mean of 1,2,3,4-tetrahydro-beta-carboline level in human plasma (n = 10) was 8.78 +/- 1.94 ng ml-1 and 5.68 +/- 1.34 ng in platelets corresponding 1 ml of platelet rich plasma.

Tetrahydro-beta-carbolines and corresponding tryptamines: In vitro inhibition of serotonin, dopamine and noradrenaline uptake in rat brain synaptosomes

The structure activity relationships of tryptolines and some other beta-carbolines and tryptamines as inhibitors of serotonin (5-HT), dopamine (DA) and noradrenaline (NA) uptake were studied in rat brain synaptosomes. All beta-carbolines inhibited to higher degree the uptake of 5-HT than that of DA or NA(IC50's 5-100 times lower). The most potent tryptoline derivative was 6-hydroxy-tetrahydro-beta-carboline (5-hydroxytryptoline, 6-OH-THBC) with an IC50 of 5.0 x 10(-7) M at a 5-HT concentration of 10(-7) M. 6-Methoxy-tetrahydro-beta-carboline (5-methoxytryptoline) was slightly weaker; the inhibition of 5-HT uptake and DA uptake being competitive. Also tetrahydro-beta-carboline (tryptoline) was more potent than its 1-methylderivative, tetrahydroharmane (methtryptoline) or norharmane (beta-carboline). All of them were, however, weaker inhibitors of 5-HT uptake than the freely rotating indoleamines N-methyl-tryptamine (N-Me-T) or 5-HT itself. N-Me-T and 5-HT were also more potent inhibitors of DA and NA uptake than most of the beta-carbolines, DA uptake, however, was inhibited better by 6-OH-THBC than by 5-HT or N-ME-T. Tetrahydro-beta-carbolines may inhibit 5-HT uptake also in vivo but is unlikely that catecholamine uptake is affected.