A metabolomics perspective on 2 years of high-intensity training in horses

The plasma metabolomic profile of elite harness horses subjected to different training programmes was explored. All horses had the same training programme from 1.5 until 2 years of age and then high-intensity training was introduced, with horses divided into high and low training groups. Morning blood samples were collected at 1.5, 2, 2.5 and 3.5 years of age. The plasma was analysed using targeted absolute quantitative analysis and a combination of tandem mass spectrometry, flow-injection analysis and liquid chromatography. Differences between the two training groups were observed at 2 years of age, when 161 metabolites and sums and ratios were lower (e.g. ceramide and several triglycerides) and 51 were higher (e.g. aconitic acid, anserine, sum of PUFA cholesteryl esters and solely ketogenic AAs) in High compared with low horses. The metabolites aconitic acid, anserine, leucine, HArg synthesis and sum of solely ketogenic AAs increased over time, while beta alanine synthesis, ceramides and indole decreased. Therefore high-intensity training promoted adaptations linked to aerobic energy production and amino acid metabolism, and potentially also affected pH-buffering and vascular and insulin responses.

Reduced high-intensity training distance in growing horses had no effect on IGF-1 concentrations, but training onset interrupted time-dependent IGF-1 decline

This study investigated plasma insulin like growth factor (IGF)-1 concentrations in 16 young Standardbred horses introduced to systematic high-intensity training at two different levels of intensity. Growth and locomotion asymmetry and correlations between these and plasma IGF-1 concentrations were also examined. From September as 1-year olds to March as 2-year olds (Period 1), all horses were subjected to the same submaximal training program. In March (start of Period 2), the horses were divided into two groups (n=8) and one group was introduced to regular high-intensity training. The other group was introduced to a program where the high-intensity exercise distances were reduced by 30%. These two training programs were maintained for the remaining 21 months of the study (Periods 2, 3, and 4). There was no effect of training group on plasma IGF-1 concentrations. A continuous decline in IGF-1 levels was observed throughout the study (P<0.0001), with one notable interruption in Period 2 when the IGF-1 concentration remained at the level seen at the start of Period 1. Growth rate of body length was equally high in Periods 1 and 2 (P>0.05). Front and hind limb asymmetry was elevated in Period 2 compared with Period 1. There were positive correlations between IGF-1 concentrations and changes in body condition score, and a negative correlation between IGF-1 concentration and weight. These results indicate that introduction to high-intensity training induces IGF-1 release in horses, but that a 30% difference in the distances used in high-intensity training does not affect IGF-1 levels. The temporary interruption in decline in IGF-1 release with the onset of high-intensity training may influence growth pattern and locomotion asymmetry, but further studies are needed to assess causality.

Complexity of dissolved organic matter in the molecular size dimension: insights from coupled size exclusion chromatography electrospray ionisation mass spectrometry

This paper investigates the relationship between apparent size distribution and molecular complexity of dissolved organic matter from the natural environment. We used a high pressure size exclusion chromatography (HPSEC) method coupled to UV-Vis diode array detection (UV-DAD) and electrospray ionisation mass spectrometry (ESI-MS) in order to compare the apparent size of natural organic matter, determined by HPSEC-UV and the molecular mass determined online by ESI-MS. We found that there was a clear discrepancy between the two methods, and found evidence for an important pool of organic matter that has a strong UV absorbance and no ESI-MS signal. Contrary to some previous research, we found no evidence that apparently high molecular weight organic matter is constituted by aggregates of low molecular weight (<1000 Da) material. Furthermore, our results suggest that the majority of apparent size variability within the ESI ionisable pool of organic matter is due to secondary interaction and exclusion effects on the HPSEC column, and not true differences in hydrodynamic size or intermolecular aggregation.

Effects of Interpolation on the Inverse Problem of Electrocardiography

Electrocardiographic Imaging (ECGI) aims to reconstruct electrograms from the body surface potential measurements. Bad leads are usually excluded from the inverse problem solution. Alternatively, interpolation can be applied. This study explores how sensitive ECGI is to different bad-lead configurations and interpolation methods. Experimental data from a Langendorff-perfused pig heart suspended in a human-shaped torso-tank was used. Epicardial electrograms were acquired during 30 s (31 beats) of RV pacing using a 108-electrode array, simultaneously with torso potentials from 128 electrodes embedded in the tank surface. Six different bad lead cases were designed based on clinical experience. Inverse problem was solved by applying Tikhonov regularization i) using the complete data, ii) bad-leads-removed data, and iii) interpolated data, with 5 different methods. Our results showed that ECGI accuracy of an interpolation method highly depends on the location of the bad leads. If they are in the high-potential-gradient regions of the torso, a highly accurate interpolation method is needed to achieve an ECGI accuracy close to using complete data. If the BSP reconstruction of the interpolation method is poor in these regions, the reconstructed electrograms also have lower accuracy, suggesting that bad leads should be removed instead of interpolated. The inverse-forward method was found to be the best among all interpolation methods applied in this study in terms of both missing BSP lead reconstruction and ECGI accuracy, even for the bad leads located over the chest.

A simplified and sensitive immunoprecipitation mass spectrometry protocol for the analysis of amyloid-beta peptides in brain tissue

In the field of Alzheimer's disease, there is an urgent need for novel analytical tools to identify disease-specific biomarkers and to evaluate therapeutics. Preclinical trials commonly employ amyloid beta (Aβ) peptide signatures as a read-out. In this paper, we report a simplified and detailed protocol for robust immunoprecipitation of Aβ in brain tissue prior to mass spectrometric detection exemplified by a study using transgenic mice. The established method employed murine monoclonal and rabbit polyclonal antibodies and was capable of yielding well-reproducible peaks of high intensity with low background signal intensities corresponding to various Aβ forms.

Impact of ocean acidification on antimicrobial activity in gills of the blue mussel (Mytilus edulis)

Here, we aimed to investigate potential effects of ocean acidification on antimicrobial peptide (AMP) activity in the gills of Mytilus edulis, as gills are directly facing seawater and the changing pH (predicted to be reduced from ∼8.1 to ∼7.7 by 2100). The AMP activity of gill and haemocyte extracts was compared at pH 6.0, 7.7 and 8.1, with a radial diffusion assay against Escherichia coli. The activity of the gill extracts was not affected by pH, while it was significantly reduced with increasing pH in the haemocyte extracts. Gill extracts were also tested against different species of Vibrio (V. parahaemolyticus, V. tubiashii, V. splendidus, V. alginolyticus) at pH 7.7 and 8.1. The metabolic activity of the bacteria decreased by ∼65-90%, depending on species of bacteria, but was, as in the radial diffusion assay, not affected by pH. The results indicated that AMPs from gills are efficient in a broad pH-range. However, when mussels were pre-exposed for pH 7.7 for four month the gill extracts presented significantly lower inhibit of bacterial growth. A full in-depth proteome investigation of gill extracts, using LC-Orbitrap MS/MS technique, showed that among previously described AMPs from haemocytes of Mytilus, myticin A was found up-regulated in response to lipopolysaccharide, 3 h post injection. Sporadic occurrence of other immune related peptides/proteins also pointed to a rapid response (0.5-3 h p.i.). Altogether, our results indicate that the gills of blue mussels constitute an important first line defence adapted to act at the pH of seawater. The antimicrobial activity of the gills is however modulated when mussels are under the pressure of ocean acidification, which may give future advantages for invading pathogens.

Time course analysis of mechanical ventilation-induced diaphragm contractile muscle dysfunction in the rat

Controlled mechanical ventilation (CMV) plays a key role in triggering the impaired diaphragm muscle function and the concomitant delayed weaning from the respirator in critically ill intensive care unit (ICU) patients. To date, experimental and clinical studies have primarily focused on early effects on the diaphragm by CMV, or at specific time points. To improve our understanding of the mechanisms underlying the impaired diaphragm muscle function in response to mechanical ventilation, we have performed time-resolved analyses between 6 h and 14 days using an experimental rat ICU model allowing detailed studies of the diaphragm in response to long-term CMV. A rapid and early decline in maximum muscle fibre force and preceding muscle fibre atrophy was observed in the diaphragm in response to CMV, resulting in an 85% reduction in residual diaphragm fibre function after 9-14 days of CMV. A modest loss of contractile proteins was observed and linked to an early activation of the ubiquitin proteasome pathway, myosin:actin ratios were not affected and the transcriptional regulation of myosin isoforms did not show any dramatic changes during the observation period. Furthermore, small angle X-ray diffraction analyses demonstrate that myosin can bind to actin in an ATP-dependent manner even after 9-14 days of exposure to CMV. Thus, quantitative changes in muscle fibre size and contractile proteins are not the dominating factors underlying the dramatic decline in diaphragm muscle function in response to CMV, in contrast to earlier observations in limb muscles. The observed early loss of subsarcolemmal neuronal nitric oxide synthase activity, onset of oxidative stress, intracellular lipid accumulation and post-translational protein modifications strongly argue for significant qualitative changes in contractile proteins causing the severely impaired residual function in diaphragm fibres after long-term mechanical ventilation. For the first time, the present study demonstrates novel changes in the diaphragm structure/function and underlying mechanisms at the gene, protein and cellular levels in response to CMV at a high temporal resolution ranging from 6 h to 14 days.

Manganese-induced parkinsonism in methcathinone abusers: bio-markers of exposure and follow-up

BACKGROUND AND PURPOSE

Methcathinone abuse is a new cause of manganism. The psychostimulant is prepared from pseudoephedrine using potassium permanganate as an oxidant. We describe the clinical, biological, neuroimaging characteristics and follow-up results in a large Estonian cohort of intravenous methcathinone users.

METHODS

During 2006-2012 we studied 38 methcathinone abusers with a mean age of 33 years. Subjects were rated by the Unified Parkinson's Disease Rating Scale (UPDRS), Hoehn and Yahr (HY), and Schwab and England (SE) rating scales. Twenty-four cases were reassessed 9-70 (20 ± 15) months after the initial evaluation. Manganese (Mn) in plasma and hair was analysed by inductively coupled plasma-atom emission spectrometry. Magnetic resonance imaging (MRI) was performed in 11, and single-photon emission computed tomography (SPECT) with iodobenzamide (IBZM) in eight subjects.

RESULTS

The average total UPDRS score was 43 ± 21. The most severely affected domains in UPDRS Part III were speech and postural stability, the least affected domain was resting tremor. At follow-up there was worsening of HY and SE rating scales. Subjects had a higher mean level of Mn in hair (2.9 ± 3.8 ppm) than controls (0.82 ± 1.02 ppm), P = 0.02. Plasma Mn concentrations were higher (11.5 ± 6.2 ppb) in active than in former users (5.6 ± 1.8 ppb), P = 0.006. Active methcathinone users had increased MRI T1-signal intensity in the globus pallidus, substantia nigra and periaquaductal gray matter. IBZM-SPECT showed normal symmetric tracer uptake in striatum.

CONCLUSION

Methcathinone abusers develop a distinctive hypokinetic syndrome. Though the biomarkers of Mn exposure are characteristic only of recent abuse, the syndrome is not reversible.

Clinical, neuroimaging and neurophysiological features in addicts with manganese-ephedrone exposure

OBJECTIVE

To identify biomarkers supporting the clinical diagnosis of manganism in patients several years after exposure to manganese (Mn).

METHODS

Neurophysiological examinations, magnetic resonance imaging (MRI), single-photon emission computed tomography and fluorodeoxyglycose (FDG) positron emission tomography were performed in four former ephedrone addicts with extrapyramidal symptoms.

RESULTS

Peripheral nervous system was not affected. No patients had reduced uptake of (123)I Ioflupane in the striatum. MRI signal intensities were slightly changed in the basal ganglia. All patients showed a widespread, but not uniform, pathological pattern of FDG uptake with changes mainly located to the central part of the brain including the basal ganglia and the surrounding white matter.

CONCLUSIONS

Presynaptic neurons in the nigrostriatal pathway are intact in Mn-induced parkinsonism after prolonged abstinence from ephedrone. The diagnosis is principally based on clinical signs and the history of drug abuse.

Irreversible motor impairment in young addicts--ephedrone, manganism or both?

BACKGROUND

Parkinsonian syndrome related to intravenous use of a "designer" psychostimulant, derived from pseudoephedrine using potassium permanganate as the oxidant, has been observed in drug addicts in Estonia.

OBJECTIVE

To describe the symptomatology of four young patients, history of drug administration and chemical analysis of a drug batch.

METHODS

Mental and motor function and quality of life were scored and ephedrone was analyzed using electrospray mass spectrometry. Manganese content of the final synthetic mixture was analyzed using Inductively Coupled Plasma-Atomic Emission Spectrometry.

RESULTS

None of the four cases scored below the dementia threshold in MMSE, while other ratings (UPDRS, H&Y, PDQ-39) corresponded to disabilities seen in relatively advanced Parkinson's disease. The ephedrone yield of the reaction was approximately 44% and the mixture was found to contain 0.6 g/l of manganese.

CONCLUSIONS

The cases were exposed to extreme manganese load. Their symptomatology is probably identical to manganism. The role of ephedrone is presently unknown. Physicians must be aware of early signs of manganism in patients within social risk groups.

Characterization of human urinary metabolites of the antimalarial piperaquine

Five metabolites of the antimalarial piperaquine (PQ) (1,3-bis-[4-(7-chloroquinolyl-4)-piperazinyl-1]-propane) have been identified and their molecular structures characterized. After a p.o. dose of dihydroartemisinin-piperaquine, urine collected over 16 h from two healthy subjects was analyzed using liquid chromatography (LC)/UV, LC/tandem mass spectrometry (MS/MS), Fourier transform ion cyclotron resonance (FTICR)/MS, and H NMR. Five different peaks were recognized as possible metabolites [M1, 320 m/z; M2, M3, and M4, 551 m/z (PQ + 16 m/z); and M5, 567 m/z (PQ + 32 m/z)] using LC/MS/MS with gradient elution. The proposed carboxylic M1 has a theoretical monoisotopic molecular mass of 320.1166 m/z, which is in accordance with the FTICR/MS (320.1168 m/z) findings. The LC/MS/MS results also showed a 551 m/z metabolite (M2) with a distinct difference both in polarity and fragmentation pattern compared with PQ, 7-hydroxypiperaquine, and the other 551 m/z metabolites. We suggest that this is caused by N-oxidation of PQ. The results showed two metabolites (M3 and M4) with a molecular ion at 551 m/z and similar fragmentation pattern as both PQ and 7-hydroxypiperaquine; therefore, they are likely to be hydroxylated PQ metabolites. The molecular structures of M1 and M2 were also confirmed using H NMR. Urinary excretion rate in one subject suggested a terminal elimination half-life of about 53 days for M1. Assuming formation rate-limiting kinetics, this would support recent findings that the terminal elimination half-life of PQ has been underestimated previously.

The norepinephrine level is decreased in the lymphocytes of long-term interferon-beta-treated multiple sclerosis patients

The mutual involvement of dopamine and its metabolites in the nervous and immune systems has the potential to provide information on the interaction of these two systems. During a 24-hour period, we used capillary electrophoresis with electrochemical detection to repeatedly measure the intracellular catecholamine concentrations in the peripheral blood lymphocytes of relapsing-remitting multiple sclerosis (RRMS) patients receiving interferon (IFN)-beta-1b (n = 13), and those of IFN-naïve RRMS patients receiving their first IFN-beta-1a injection (n = 19) during this study, and compared them with the levels in healthy controls (n = 12). At baseline, the norepinephrine level was significantly decreased (P =0.003) in the long-term IFN MS patients compared with the controls. The Time x Group interactions for dopamine (P=0.5854) and norepinephrine (P=0.6192) were not significant. The group effects for the individual drugs were P=0.3529 and 0.1282, respectively. The lower norepinephrine level at baseline in the long-term IFN MS group suggests an immunologically stable phase, in line with our previous findings. This is the first report of the effects of IFN-beta administration on intracellular catecholamines in MS patients. Further studies are necessary to elucidate the immune reactions affected by the catecholamines in MS and to evaluate the roles of these potential immunotransmitters.

Molecular differentiation of ischemic and valvular heart disease by liquid chromatography/fourier transform ion cyclotron resonance mass spectrometry

Proteomic patterns of myocardial tissue in different etiologies of heart failure were investigated using a direct analytical approach with High Performance Liquid Chromatography (HPLC)/Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS). Right atrial appendages from 20 patients, 10 with hemodynamically significant isolated aortic valve disease and 10 with symptomatic coronary artery disease were collected during elective cardiac surgery. After preparation of tissue samples and tryptic digestion of proteins, the peptide mixture was HPLC-separated and on-line analyzed by electrospray FT-ICR MS. Data obtained from HPLC / FT-ICR MS runs were compared for classification. To extract the classification features, the selection of best individual features was applied and the "nearest mean classifier" was used for the classification of test samples and the sample projection onto classification patterns. The pattern distribution characteristics of aortic and coronary diseases were clearly different. No interference between samples of both disease categories was registered, even if the distribution of unsupervised classified test samples were closer. Samples representing aortic valve disease showed a closer accumulation pattern of spots compared to the samples representing coronary disease, which indicated a more specific protein classification. Through selective identification of specific peptides and protein patterns with FTMS, valvular and coronary heart disease is for the first time clearly distinguished at molecular level. The described methodology could also be feasible in search for specific biomarkers in plasma or serum for diagnostic purposes.

Interferon-beta affects the tryptophan metabolism in multiple sclerosis patients

Tryptophan and its metabolites are of great interest in understanding the pathogenesis of multiple sclerosis (MS). The total levels of tryptophan and its metabolites, kynurenine and kynurenic acid were determined in plasma by capillary liquid chromatography electrospray ionisation tandem mass spectrometry. This is the first report of the plasma levels of these analytes in healthy controls and relapsing-remitting MS patients receiving long-term and acute interferon-beta (IFN-beta) treatment. Twenty-four hours post-administration increased kynurenine levels (first IFN MS versus healthy, P = 0.042) and kynurenine/tryptophan ratio (K/T; first IFN MS versus healthy, P =0.027; first IFN MS versus long-term IFN MS, P = 0.036) were found. The long-term IFN MS group had higher K/T ratios at 4 and 12 h post-administration (P = 0.015 and 0.009, respectively). The increase of K/T ratio in the first IFN MS group indicate an induction of the enzyme indolamine-2,3-dioxygenase (IDO), as reported earlier in experimental allergic encephalomyelitis. As IDO is participating in both inflammatory and neurodegenerative processes, further knowledge of its involvement in the pathogenesis of MS is of great importance.

Tensile strength, histological and immunohistochemical observations of periodontal wound healing in the dog

This study was designed to study wound strength at the dentine/connective tissue interface and at the bone/connective tissue interface following full thickness flap surgery. Flaps of uniform dimension were outlined in four young adult beagle dogs using a standardised double bladed knife and vertical incisions 10 mm apart, which extended 8 mm apical to the gingival margin. Bone was removed from half the sites (eight sites in each dog), giving 32 flaps replaced on dentine and 32 sites on bone. A tensile force was applied using a microprocessor force gauge at 1, 2, 3, 7, 10, 14, 21, and 28 days. Mean tensile strengths were markedly weaker for the dentine/flap interface. At 7 days the value for flaps to dentine was 1.82 N, in contrast to 5.08 N for flaps replaced on bone. Inflammatory cell counts tended to fall markedly at 3 days for both modalities, but were higher for the dentine/flap modality at all time points. Fibroblast density peaked at 7-14 days but did not vary with type of flap over the time points studied. The amounts of fibrin were greater for the dentine/flap interface at all time points but decreased for both flap types as time progressed. Collagen type V was localised to the basement membrane and blood vessels and tended to show more foci for flaps replaced on dentine. Procollagen levels showed little change over the healing interval for both flap/bone and flap/dentine interfaces. Type III collagen synthesis was at peak levels during the first week. These findings would support efforts to stabilise periodontal flaps at early time points, especially those on dentine.

Enhanced microdialysis of neuropeptides

An enhanced microdialysis method for neuropeptides is described and some preliminary results of this novel approach are presented. The enhancement is achieved by adding a vehicle (solid support) to the perfusion fluid in order to increase the diffusion coefficient across the membrane and efficiently transport the analytes towards the detector. The microdialysis samples are desalted and then analyzed on an electrospray ionization orthogonal time-of-flight mass spectrometer. The preliminary results show major increase in signal when comparing this new approach of microdialysis with ordinary microdialysis.

Micro-capillary liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry--a powerful tool for peptide and protein identification

In order to be able to study complex biological samples, a micro-capillary liquid chromatography system was coupled to a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer. The setup was tested on a tryptic digest of bovine serum albumin, which resulted in high sequence coverage (> 92%) of the protein.

Micro-capillary liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry--a powerful tool for peptide and protein identification

In order to be able to study complex biological samples, a micro-capillary liquid chromatography system was coupled to a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer. The setup was tested on a tryptic digest of bovine serum albumin, which resulted in high sequence coverage (> 92%) of the protein.

Enhanced microdialysis of neuropeptides

An enhanced microdialysis method for neuropeptides is described and some preliminary results of this novel approach are presented. The enhancement is achieved by adding a vehicle (solid support) to the perfusion fluid in order to increase the diffusion coefficient across the membrane and efficiently transport the analytes towards the detector. The microdialysis samples are desalted and then analyzed on an electrospray ionization orthogonal time-of-flight mass spectrometer. The preliminary results show major increase in signal when comparing this new approach of microdialysis with ordinary microdialysis.

Future aspects of psychoneuroimmunology - lymphocyte peptides reflecting psychiatric disorders studied by mass spectrometry

We have investigated whether cytoplasmatic and nuclear extracts of human peripheral blood lymphocytes contain arginine vasopressin (AVP), of importance for memory functions, in samples from healthy controls and patients diagnosed as depressed. It is the first time as AVP, AVP-fragments and chemically modified AVP-forms have been demonstrated in lymphocyte/nuclear extracts. This was performed by an HPLC-purification step, followed by a second immunoprecipitation step before identification by mass spectrometry. We are developing new methods using a combination of high-resolution mass spectrometry and separation techniques such as capillary electrophoresis and nano liquid chromatography. We have named this methodological approach when studying endogenous peptides -Peptidomics.

Downsizing proteolytic digestion and analysis using dispenser-aided sample handling and nanovial matrix-assisted laser/desorption ionization-target arrays

An efficient technique for enzymatic digestion of proteins in nanovial arrays and identification by peptide mass fingerprinting using matrix-assisted laser desorption/ionization (MALDI-MS) is presented in this work. Through dispensing of a protein solution with simultaneous evaporation the protein (substrate) is concentrated up to 300 times in-vial. At higher substrate concentrations the catalytic turnover numbers increase according to the Michaelis-Menten kinetics. Therefore, the dispenser-aided nanodigestion is valuable for identification of low-level proteins (10 nM-500 nM) as well as for automatic high efficiency digestions performed in 0.2-10 min. As an example of low-level protein identification, a 10 nM solution of lysozyme C was unambiguously identified after 5 min of nanodigestion. Moreover, only 30 s nanodigestion was sufficient to identify hemoglobin (10 microM), exemplifying the fast catalysis of the nanodigestion technique. The developed silicon flow-through piezoelectric dispenser is adapted for low-volume and preconcentrated samples in the nL-microL range and provides fast, accurate and contact-free sample positioning into the nanovials. In this work, the properties of the nanodigestion concept regarding proteins of different characteristics are explored. Furthermore, the potential of automated protein identification using precoated proteolytic nanovial-arrays is demonstrated.

Identification of nuclei associated proteins by 2D-gel electrophoresis and mass spectrometry

In clinical neuroscience as well as in many other clinical disciplines, the completion of the human genome project offers a new possibility to identify and localize the products of the genes, the proteins. Nuclear proteins are synthesized in the cytoplasm and imported into the nucleus by multiple pathways. The mechanisms by which nuclear accumulation of different molecular species occur are unclear but it is apparent that changes in the cellular and molecular events associated with the accumulation of nuclear proteins sometimes precedes transformation of cells into diseased states. The significance of the accumulation and the operation of nuclear proteins remain to be elucidated in detail. Such knowledge will play a key role in the understanding of the regulation of transcription and its disturbances in several of our most devastating diseases. In this paper we present a strategy to identify nuclear associated proteins in small samples by using two-dimensional electrophoresis and mass spectrometry. We have used human blood lymphocytes as a model, but the method should be rather general for any kind of tissue. Twenty two proteins were randomly chosen, and of these 18 proteins were identified by database searching of mass spectrometric data, obtained from in-gel tryptic digests of the spots. Thirteen proteins recently described with nuclear localization and function were identified, and five proteins; calgranulin B, glyceraldehyde-3-phosphate dehydrogenase (G3P2), a TATA-binding protein (ATBP), tubulin beta chain and moesin were also identified as being nuclear associated. The presented data clearly shows of the great role of two-dimensional gel electrophoresis and modern mass spectrometry in the excavation of the protein patterns on the subcellular level, and the ability to use small samples well suited for clinical screening.

Stereoselective determination of amino acids in beta-amyloid peptides and senile plaques

A novel method for the determination of the enantiomeric composition of peptides is presented. In this paper, the focus has been on beta-amyloid peptides from deceased Alzheimer's disease patients. The peptides are hydrolyzed using mineral acid. The free amino acids are derivatized with the chiral reagent (+)- or (-)-1-(9-anthryl)-2-propyl chloroformate and subsequently separated using micellar electrokinetic chromatography (MEKC) and detected using laser-induced fluorescence (LIF) detection. The high separation efficiency of the MEKC-LIF system, yielding approximately 1 million theoretical plates/m for most amino acids, facilitates the simultaneous chiral determination of nine amino acids. The samples that have been analyzed were standard 1-40 beta-amyloid peptides, in vitro precipitated beta-amyloid fibrils, and human senile plaque samples.

Nuclear factor-kappa B is involved in the catecholaminergic suppression of immunocompetent cells

Catecholamines are known to exert a powerful impact on the immune system by downregulation of proliferation and differentiation, and induction of apoptosis. However, the mechanism for this regulatory route is still unclear. Therefore well established human monocytic cell-lines and nontransformed human monocytes, obtained from peripheral blood, were incubated with an optimal concentration of LPS and varying concentrations of the catecholamine dopamine. The proliferative response to LPS was determined by [3H]thymidine incorporation, and a significant suppressive effect by dopamine was obtained. LPS-induced binding of NF-kappa B to DNA, determined by electrophoretic mobility shift assay, was inhibited by extrinsic dopamine, leading to a decreased proliferation and cytokine expression. In contrast, the intracellular ceramide concentration was not affected by incubation of peripheral blood lymphocytes with dopamine. Our findings suggest that the NF-kappa B-I-kappa B transcription machinery may well be involved in the catecholaminergic regulation of the immune system, while the ceramide-SAPK/JNK cascade appears not to play a significant role in this suppression.

A CE-MALDI interface based on the use of prestructured sample supports

We have developed an off-line coupling of capillary electrophoresis (CE) to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS) based on CE fraction collection onto prestructured MALDI sample supports. Analyte carryover and detection sensitivity were investigated using a standard peptide mixture. Low femtomole amounts were detected, and no noticeable carryover was discovered. The performance of the method was evaluated with a mixture of tryptic digests of proteins from a human fetal brain cDNA expression library. The total number of identified peptides was increased from 47 to 211 when the CE-MALDI interface was used compared to direct MALDI-MS analysis. Sequence coverage with CE-MALDI was in the 25-60% range for the different proteins, corresponding to an increase of 1.3-4.9 times relative to that obtained with MALDI-MS of the crude mixture. Fractionation of sample components also facilitated protein identification by MALDI postsource decay analysis. Our initial results suggest this CE-MALDI interface can be used for the analysis of complex peptide mixtures isolated from biological tissues.

A simple and robust conductive graphite coating for sheathless electrospray emitters used in capillary electrophoresis/mass spectrometry

A graphite-polyimide mixture was used as a conductive coating for sheathless electrospray emitters. The coating procedure described is simple and inexpensive compared to previously described methods. An investigation of the stability of the conductive coating carried out by electrochemical methods revealed good performances during oxidative stress. In addition, no decrease in emitter performance was seen during continuous electrospray in the positive electrospray mode for two weeks. Fast capillary electrophoresis with attomole sensitivity demonstrated the excellent performance of the described sheathless interface when used in conjunction with an orthogonal time-of-flight mass spectrometer. The overall simplicity, stability and low cost of this type of sheathless emitter make the described approach highly suitable for any on-column coupling of low flow rate separation techniques to a mass spectrometer.

Rapid method to characterize mutations in transthyretin in cerebrospinal fluid from familial amyloidotic polyneuropathy patients by use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

BACKGROUND

Familial amyloidotic polyneuropathy (FAP) type I, the most common dominantly inherited form of amyloidosis, is caused by a Val-to-Met point mutation at position 30 (Val(30)-->Met) in the protein transthyretin. Mass spectrometric analysis can identify modification of proteins, such as point mutations, acetylation, phosphorylation, sulfation, oxidation, and glycosylation.

METHODS

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) spectra from cerebrospinal fluid (CSF) drawn from a patient with FAP were compared with CSF from controls. We also isolated transthyretin with a Centrisart molecular size cutoff filter and performed high-accuracy peptide mass mapping to localize the site of the amino acid substitution (Val(30)-->Met).

RESULTS

Mass spectra of transthyretin were produced directly from human CSF as well as from CSF after a simple prepurification method without immunoprecipitation. On-target tryptic digestion and MALDI-MS verified mass spectrometric peak identification. The point mutation was still detectable in CSF after hepatic transplantation.

CONCLUSIONS

It is possible to diagnose FAP by a rapid MALDI-TOF MS analysis using only 100 microL of CSF, with only 250 nL actually consumed on target. The approach may also be useful to monitor production of mutated transthyretin by choroid plexus, especially after liver transplantation.

Chiral separation of amino acids in biological fluids by micellar electrokinetic chromatography with laser-induced fluorescence detection

A method is presented for the chiral analysis of amino acids in biological fluids using micellar electrokinetic chromatography (MEKC) and laser-induced fluorescence (LIF). The amino acids are derivatized with the chiral reagent (+/-)-1-(9-anthryl)-2-propyl chloroformate (APOC) and separated using a mixed micellar separation system. No tedious pre-purification of samples is required. The excellent separation efficiency and good detection capabilities of the MEKC-LIF system are exemplified in the analysis of urine and cerebrospinal fluid. This is the first time MEKC has been reported for chiral analysis of amino acids in biological fluids. The amino acids D-alanine, D-glutamine, and D-aspartic acid have been observed in cerebrospinal fluid, and D-alanine and D-glutamic acid in urine. To the best of our knowledge no measurements of either D-alanine in cerebrospinal fluid or D-glutamic acid in urine have been presented in the literature before.

High-mannose-type oligosaccharides from human placental arylsulfatase A are core fucosylated as confirmed by MALDI MS

Despite numerous studies on arylsulfatase A, the structure of its glycans is not well understood. It has been shown that the concentration of arylsulfatase A increases in the body fluids of patients with some forms of cancer, and the carbohydrate component of arylsulfatase A synthesized in tumor tissues and transformed cells undergoes increased sialylation, phosphorylation and sulfation. To understand the significance of any changes in the glycosylation of arylsulfatase A in cancer, it is important to know the structure of its carbohydrate component in normal tissue. In the present study we have analyzed carbohydrate moieties of human placental arylsylfatase A using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by Western blotting on Immobilon P and on-blot deglycosylation using PNGase F for glycan release. Profiles of N-glycans were obtained by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). Oligosaccharides were sequenced using specific exoglycosidases, and digestion products were analyzed by MALDI MS and the computer matching of the resulting masses with those derived from a sequence database. Fifty picomoles (6 microg) of arylsulfatase A applied to the gel were sufficient to characterize its oligosaccharide content. The results indicated that human placental arylsulfatase A possesses only high-mannose-type oligosaccharides, of which almost half are core fucosylated. In addition, there was a minor species of high-mannose-type glycan bearing six mannose residues with a core fucose. This structure was not expected since high-mannose-type oligosaccharides basically have not been recognized as a substrate for the alpha1,6-fucosyltransferase.

Analysis of enzymatically digested proteins and protein mixtures using a 9.4 Tesla Fourier transform ion cyclotron mass spectrometer

A commercially available 9.4 Tesla Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was applied in the analysis of tryptic digests of protein mixtures without any separation. First, the method was demonstrated on a mixture of tryptic digests of equine cytochrome c, equine myoglobin and bovine serum albumin. The same method was then applied to human plasma from a healthy blood donor. Computer programs were employed to simplify analysis of the complex spectra. The 2745 peaks in the human plasma electrospray ionization FTICR spectrum could be reduced to 1165 isotopic clusters and 669 unique masses. Out of these, 82 masses matched tryptic fragments of serum albumin with mass measurement errors less than 10 ppm, covering 93% of the sequence. Another 16 masses were assigned to tryptic fragments of transferrin, covering 41% of the sequence on the 10 ppm mass measurement error level (14 within 2 ppm). The mass measurement errors were approximately normal distributed with a standard deviation of 1.7 ppm. This demonstrates the feasibility of combining the ultra-high mass resolving power and accuracy of FTICR mass spectrometry with automated computer analysis for investigating complex biological matrices.

Identification of defensins in human lymphocyte nuclei

The cell nucleus plays an essential role in all aspects of cell function and regulation. Most of the nuclear proteins/peptides are synthesized in the cytoplasm and transported into the nucleus through the nuclear pore complexes. The nuclear proteins/peptides conjugate with each other and interact in transcriptional activation/inactivation. Several of the high molecular mass transcription factors (> 30 kDa) have been identified and characterized. However, the information on the low molecular mass proteins/peptides of the nucleus is limited. We have investigated these low molecular mass proteins/peptides from the nucleus of human peripheral blood lymphocytes using reversed-phase high-performance liquid chromatography (RP-HPLC). The HPLC fractions were further analysed by matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry, electrospray ionization time of flight (ESI-TOF) mass spectrometry and electrospray ionization fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry for mass determination. Using this combination of mass spectrometry techniques and microsequence analysis, we have shown that human lymphocyte nuclei contain defensins, a mixture of human neutrophil granule peptide 1, 2 and 3.

Homogeneous sample preparation for automated high throughput analysis with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry

This work presents a simple method for obtaining homogeneous sample surfaces in matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) for the automated analysis of peptides and proteins. The sample preparation method is based on applying the sample/matrix mixture onto a pre-deposited highly diluted matrix spot. The pre-deposited crystals act as seeds for the new sample containing crystals which become much smaller in size and more evenly distributed than with conventional methods. This 'seed-layer' method was developed, optimised and compared with the dried-droplet method using peptides and proteins in the 1000-20,000 Da range. The seed-layer method increases the surface homogeneity, spot to spot reproducibility and sample washability as compared with the commonly used dried-droplet method. This methodology is applicable to alpha-cyanohydroxycinnamic acid, sinapinic acid and ferulic acid, which all form homogeneous crystal surfaces. Within-spot variation and between-spot variation was investigated using statistics at a 95% confidence level (n = 36). The statistical values were generated from more than 5000 data points collected from 500 spectra. More than 90% of the sample locations results in high intensity spectra with relatively low standard deviations (RSDs). Typically obtained data showed an RSD of 19-35% within a sample spot as well as in-between spots for proteins, and an RSD of < or = 50% for peptides. Linear calibration curves were obtained within one order of magnitude using internal calibration with a point-RSD of 3% (n = 10). The sample homogeneity allows mass spectra (average of 16 laser shots) to be obtained on each individual sample within 15 sec, whereby a 100 spot target plate can be run in 25 min. High density target plates using the seed-layer method were prepared by spotting approximately 100 picoliter droplets onto the target, resulting in sample spots < or = 500 microns in diameter using a flow-through piezo-electric micro-dispenser. By using this automated sample preparation step lower standard deviations are obtained in comparison to manually prepared samples.

Homogeneous sample preparation for automated high throughput analysis with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry

This work presents a simple method for obtaining homogeneous sample surfaces in matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) for the automated analysis of peptides and proteins. The sample preparation method is based on applying the sample/matrix mixture onto a pre-deposited highly diluted matrix spot. The pre-deposited crystals act as seeds for the new sample containing crystals which become much smaller in size and more evenly distributed than with conventional methods. This 'seed-layer' method was developed, optimised and compared with the dried-droplet method using peptides and proteins in the 1000-20,000 Da range. The seed-layer method increases the surface homogeneity, spot to spot reproducibility and sample washability as compared with the commonly used dried-droplet method. This methodology is applicable to alpha-cyanohydroxycinnamic acid, sinapinic acid and ferulic acid, which all form homogeneous crystal surfaces. Within-spot variation and between-spot variation was investigated using statistics at a 95% confidence level (n = 36). The statistical values were generated from more than 5000 data points collected from 500 spectra. More than 90% of the sample locations results in high intensity spectra with relatively low standard deviations (RSDs). Typically obtained data showed an RSD of 19-35% within a sample spot as well as in-between spots for proteins, and an RSD of < or = 50% for peptides. Linear calibration curves were obtained within one order of magnitude using internal calibration with a point-RSD of 3% (n = 10). The sample homogeneity allows mass spectra (average of 16 laser shots) to be obtained on each individual sample within 15 sec, whereby a 100 spot target plate can be run in 25 min. High density target plates using the seed-layer method were prepared by spotting approximately 100 picoliter droplets onto the target, resulting in sample spots < or = 500 microns in diameter using a flow-through piezo-electric micro-dispenser. By using this automated sample preparation step lower standard deviations are obtained in comparison to manually prepared samples.

Investigation of the operative response of a group of general dental practitioners to varying extents of proximal caries

The aim of this investigation was to assess the operative response of a representative sample of Irish General Dental Practitioners of various times since qualification to carious lesions of varying extent in both approximal surfaces of a lower left first molar tooth. 82 General Dental practitioners participated. The dentists were asked to treat 2 manikin teeth for minimal caries on both approximal surfaces extending to the enamel dentine junction, 2 teeth for caries extending approximately to half the thickness of the dentine and 2 teeth for caries extending more than 3/4 of the dentine thickness. Weight measurements were made of the tooth substance cut away. Mean volumes of tooth material removed ranged from 21 mm3 for minimal caries to 76 mm3 for the largest amount of caries. A two-factor analysis of variance revealed that the type of cavity preparation the dentist used had a significant effect on the volume of tooth material removed for all three extents of caries. Time since graduation had a significant effect on the volume of tooth material removed for the least extent of caries, but not for the other categories of carious involvement.

Mass spectrometry of peptides in neuroscience

This review focuses on the contributions of modern mass spectrometry to neuropeptide research. An introduction to newer mass spectrometric techniques is provided. Also, the use of mass spectrometry in combination with high-resolution separation techniques for neuropeptide identification in biological samples is illustrated. The amino acid sequence information that is important for the identification and analysis of known, novel, or chemically modified neuropeptides may be obtained using mass spectrometric techniques. Because mass spectrometry techniques can be used to reflect the dynamic properties associated with neuropeptide processing in biological systems, they may be used in the future to monitor peptide profiles within organisms in response to environmental challenges such as disease and stress.

Identification of catecholamines in the immune system by electrospray ionization mass spectrometry

The first evidence that catecholamines might be present in the immune system was provided by capillary electrophoresis combined with electrochemical detection. Here, we present the first structural characterization of the endogenous catecholamines isolated from human peripheral blood mononuclear cells. Dopamine, L-DOPA and norepinephrine were detected and were identified with electrospray ionization mass spectrometry by determination of the protonated molecular species of each catecholamine and their major fragments generated in the electrospray source with a nozzle-skimmer voltage method. This technique, in conjunction with accurate mass measurement, allowed us to identify in an unfractionated sample the content of catecholamines in extracted cells in a quantitative manner, with structure-specific methodology. The data unambiguously confirm our previous tentative findings, and also strengthen the importance of the regulatory function of catecholamines in the immune system and the existence of an autocrine loop, where lymphocytes may down-regulate their own activity.

Measurements of catecholamine-mediated apoptosis of immunocompetent cells by capillary electrophoresis

Single cell analysis with capillary electrophoresis, a technique capable of detecting zeptomole quantities (10(-21) mole) of neurochemical species, has been used to demonstrate that lymphocytes are capable of active synthesis of dopamine and norepinephrine. Exposure of lymphocytes to catecholamines at concentrations as low as 10 nM leads to decreased proliferation and differentiation, e.g. interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and immunoglobulin (Ig). In addition, both inhibition of dopamine uptake with nomifensine and inhibition of packing of catecholamines into vesicles with tetrabenazine, results in significantly lower levels of dopamine and norepinephrine (p < 0.01 and p < 0.05, respectively). The catecholamine-dependent inhibition of T- and B-lymphocyte activity is mediated via an induction of a Bcl-2/Bax and Fas/FasL involved apoptosis. These findings indicate a novel mechanism for regulation of lymphocyte activity in the central nervous system, whereby elevated regional levels of catecholamines might lead to the immunoprivilege of the brain.

Patterns of attachment loss in advanced periodontitis patients monitored following initial periodontal treatment

2 main concepts seem to exist for the progression of periodontitis: (1) a slow continuous process of attachment loss; (2) periodic bursts of activity followed by quiescence or remission. This study addresses this problem and presents data for 69 sites having experienced a net loss of probing attachment amounting to > or = 3.0 mm over 42 months. The sites originated from 16 adult patients monitored after nonsurgical treatment of advanced chronic periodontitis. Probing attachment level recordings were obtained every 3rd month. The sequential probing attachment level data for each site were smoothed using cubic splines. Subjective evaluation of the raw and the smoothed data from the study sites suggested that the majority of the sites seemed to lose probing attachment in a continuous fashion, and over periods of 12 months or more. The smoothed curves were subjected to principal components analysis, which allowed the 69 sites to be ordered according to curve similarity. Nonparametric runs test failed to show that the shape of the curves for the sites was significantly associated with any of the following characteristics: patient, tooth type, tooth surface, initial probing depth, bleeding frequency, occurrence of suppuration, or a combination of inflammatory characteristics of sites.

Local administration of morphine decreases the extracellular level of GABA in the periaqueductal gray matter of freely moving rats

Opioids are generally believed to activate descending pain inhibitory pathways from the periaqueductal gray matter (PAG). Since opioids exert an inhibitory effect on neural excitability and transmitter release, an opioid-mediated inhibition of tonically active inhibitory gamma-aminobutyric acid (GABA) neurons has been suggested to mediate this effect. The aim of the present microdialysis study was to investigate the effect of local administration of morphine on the extracellular GABA level in the PAG of awake rats. The recently developed and highly sensitive method of capillary electrophoresis with laser-induced fluorescence detection was used for GABA determination in microdialysate samples obtained from the PAG of freely moving rats. The basal GABA level was 54.5 +/- 6.6 nM (n = 8; mean +/- SEM). Perfusion of the dialysis probe with morphine (100 microM) for 30 min significantly decreased the GABA level to 28.2 +/- 4.2 nM (n = 8; P < 0.05). The effect of morphine was reversed by coperfusion with naloxone (100 microM in the perfusion fluid). The present results thus provide direct experimental evidence for an opioid-induced inhibition of tonic GABA release in the PAG, which may in turn lead to a disinhibition of descending pain inhibitory pathways.

Catecholamines are synthesized by mouse lymphocytes and regulate function of these cells by induction of apoptosis

The immune and the nervous systems are anatomically closely related and interact with each other by molecules common to both systems, such as cytokines and neurotransmitters. The purpose of this study was to investigate the participation of catecholamines in the neuroimmunological network. The ability of immune cells to produce catecholamines was examined by a highly sensitive capillary electrophoresis assay, which permits detection of easily oxidized catecholamines in the zeptomole (10(-21)) range. In addition, the effects of catecholamines on in vitro proliferation, differentiation and apoptosis of lymphocytes were assessed. Mouse spleen cells and macrophages contained on average 7 x 10(-17) and 2 x 10(-17) mole dopamine per cell, respectively. In the former cell population also norepinephrine was found. Several mouse B- and T-cell hybridomas were also shown to contain endogenously produced dopamine in levels ranging from 7 x 10(-20) to 2 x 10(-18) mole dopamine per cell. In addition, one of the T-cell hybridomas proved to synthesize norepinephrine. The dopamine production of lymphocytes was blocked by the tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine, whereas incubation with the precursor L-DOPA increased the dopamine content. Incubation with L-DOPA, dopamine and norepinephrine dose-dependently suppressed mitogen induced proliferation and differentiation of mouse lymphocytes. Even short-time pretreatment of lymphocytes with L-DOPA and dopamine strongly suppressed lymphocyte proliferation and cytokine production. Incubation of lymphoid cells with L-DOPA, dopamine and norepinephrine dose-dependently induced apoptosis which, at least partly, explains the suppressive effects of catecholamines on lymphocyte function. Our results demonstrate that catecholamines: (i) are actively produced by lymphocytes and (ii) have the capacity to act as auto- and/or paracrine regulators of lymphocyte activity through induction of apoptosis.

Capillary electrophoresis with laser-induced fluorescence detection: a sensitive method for monitoring extracellular concentrations of amino acids in the periaqueductal grey matter

The use of capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) for the analysis of microdialysate samples from the periaqueductal grey matter (PAG) of freely moving rats is described. By employing 3-(4-carboxybenzoyl)-2-quinoline-carboxaldehyde (CBQCA) as a derivatization agent, we simultaneously monitored the concentrations of 8 amino acids (arginine, glutamine, valine, gamma-amino-n-butyric acid (GABA), alanine, glycine, glutamate, and aspartate), with nanomolar and subnanomolar detection limits. Two of the amino acids (GABA and glutamate) were analysed in parallel by conventional high-performance liquid chromatography (HPLC) in order to directly compare the two analytical methods. Other CE methods for analysis of microdialysate have been previously described, and this improved method offers greater sensitivity, ease of use, and the possibility to monitor several amino acids simultaneously. By using this technique together with an optimised form of microdialysis technique, the tiny sample consumption and the improved detection limits permit the detection of fast and transient transmitter changes.