Amino acid derivatives from Lucilia sericata excretions/secretions may contribute to the beneficial effects of maggot therapy via increased angiogenesis.

BACKGROUND: Maggot therapy, utilizing the larvae of Lucilia sericata, has been reported to reduce the bacterial load within wounds and also to enhance wound healing. Maggot excretions/secretions (ES) have been shown to have a role in the success of maggot therapy. While the protein content of ES has been investigated, to date little research has focused on the small metabolites present in ES and their potential contribution to the therapy. Study of the molecular composition of the secretions and the potential bioactivities present will allow for a more detailed evaluation of the efficacy of maggot therapy. OBJECTIVES: We studied the amino acid-like compounds present in ES of L. sericata larvae in order to determine the compounds present and their potential role in the wound healing process. METHODS: These included thin-layer chromatography/mass spectrometric analysis of ES to identify amino acid-like components, a turbidometric assay to investigate their potential antibacterial activity and cell proliferation studies to investigate their potential mitogenic ability. RESULTS: Three prominent compounds were detected and identified as histidine, valinol and 3-guanidinopropionic acid. While these amino acids were not shown to exhibit antibacterial activity, a proliferative effect on the growth of human endothelial cells, but not fibroblasts, was noted. CONCLUSIONS: The demonstrated proliferative effect, selectively on endothelial cells, suggests that the amino acid-like compounds present in maggot ES may have a role in wound healing, by stimulating angiogenesis.

Investigation of uremic analytes in hemodialysate and their structural elucidation from accurate mass maps generated by a multi-dimensional liquid chromatography/mass spectrometry approach.

Historically, structural elucidation of unknown analytes by mass spectrometry alone has involved tandem mass spectrometry experiments using electron ionization. Most target molecules for bioanalysis in the metabolome are unsuitable for detection by this previous methodology. Recent publications have used high-resolution accurate mass analysis using an LTQ-Orbitrap with the more modern approach of electrospray ionization to identify new metabolites of known metabolic pathways. We have investigated the use of this methodology to build accurate mass fragmentation maps for the structural elucidation of unknown compounds. This has included the development and validation of a novel multi-dimensional LC/MS/MS methodology to identify known uremic analytes in a clinical hemodialysate sample. Good inter- and intra-day reproducibility of both chromatographic stages with a high degree of mass accuracy and precision was achieved with the multi-dimensional liquid chromatography/tandem mass spectrometry (LC/MS/MS) system. Fragmentation maps were generated most successfully using collision-induced dissociation (CID) as, unlike high-energy CID (HCD), ions formed by this technique could be fragmented further. Structural elucidation is more challenging for large analytes >270 Da and distinguishing between isomers where their initial fragmentation pattern is insufficiently different. For small molecules (<200 Da), where fragmentation data may be obtained without loss of signal intensity, complete structures can be proposed from just the accurate mass fragmentation data. This methodology has led to the discovery of a selection of known uremic analytes and two completely novel moieties with chemical structural assignments made.

Online immobilized metal affinity chromatography/mass spectrometric analysis of changes elicited by cCMP in the murine brain phosphoproteome.

An automated online immobilized metal affinity chromatography/high-performance liquid chromatography mass spectrometric (IMAC-HPLC/MS/MS) method was developed to study cytidine 3',5'-cyclic monophosphate (cCMP)-specific protein phosphorylation, analogous to a previously successful offline IMAC method using microvolume IMAC pipette tips. The optimized method identified murine brain phosphoproteins selectively modified by challenge with cCMP, using manual interpretation of the results to confirm both phosphorylation and selectivity of response to cCMP. A number of proteins identified by this strategy have potential roles in hyperproliferation, a previously reported response to elevated levels of cCMP.

Fingerprint profile of Ginkgo biloba nutritional supplements by LC/ESI-MS/MS.

Ginkgo biloba is one of the most popular herb nutrition supplements, with terpene lactones and flavonoids being the two major active components. A fingerprint profile method was developed using a capillary HPLC/MS method which can identify more than 70 components from the G. biloba product. The method allows the flavonoids and terpene lactones to be detected simultaneously and information of both the parent ion and its fragmentation can be obtained in just one HPLC/MS run. Targeted post-acquisition analysis allows mass spectrometric information regarding the identification of flavonoid components to be easily distinguished from other data, however the same approach for terpene lactones was less successful due to dimer formation and requires further development. The fingerprint profiles of five commercial G. biloba nutritional supplements were obtained and compared; variation of some components among the samples was observed and fortification could be detected. In the quality control analysis of the G. biloba product this method could be viewed as complementary to specific quantitative analysis of some bioactive components of the herb.

Prenatal three-dimensional ultrasound: perception of sonographers, sonologists and undergraduate students.

OBJECTIVE: To assess the perception of non-pregnant sonographers, sonologists and undergraduate students on the use of three-dimensional (3D) ultrasound technology in fetal medicine. METHODS: This was a study of two groups of non-pregnant subjects. Group I included 520 (305 female, 215 male) medical professionals who completed a questionnaire after attending a lecture on 3D imaging. Factors such as gender, career and having children were analyzed with respect to the attendee's responses about use of 3D ultrasound for medical purposes and for reassurance. Group II included 137 (75 female, 60 male, two unknown) undergraduate students from bioengineering, psychology and physiology classes who completed a questionnaire after attending a brief presentation on two-dimensional and 3D fetal imaging. Factors such as gender and area of educational interest were analyzed with respect to the students' responses about the use of 3D ultrasound for medical purposes and for parental-fetal attachment. RESULTS: In Group I, 63% said that they would like to have a 3D ultrasound examination in the future, while 14% said that they would not. Common reasons given for wanting a 3D ultrasound exam in the future were for medical purposes (39%) or reassurance (18%). The main differences perceived between two-dimensional (2D) and 3D ultrasound were medical advantages (65%) and parental reassurance (28%). 62.4% of Group I thought 3D technology should be in wide use in obstetric ultrasound and 73.6% thought that 3D ultrasound would reassure parents carrying normal fetuses. Gender, age and career did not have a significant influence on perception of 3D ultrasound. In Group II, the majority (91%) said they could see a remarkable difference between 2D and 3D ultrasound. 83% responded that they would like to have a 3D ultrasound examination of their own baby in the future for the following reasons: 34% for the detailed picture, 31% for increased abnormality detection, 13% for reassurance or curiosity; 8% thought it would be unnecessary or a negative experience. Concerning parental-fetal attachment, 72% thought 3D ultrasound would have a positive effect. The majority of Group II (93%) thought 3D ultrasound would be valuable and 56% thought 3D ultrasound would assist in diagnosing fetal abnormalities. There was no significant relationship between gender, age or area of interest and the perception of 3D ultrasound. CONCLUSIONS: Responses by sonographers and physicians suggest that 3D ultrasound will have a role in the future for medical indications and in reassuring patients carrying normal fetuses. Our results also suggest that undergraduate students believe that 3D ultrasound will be a valuable technique in obstetrics and that it will have a positive effect on parental-fetal attachment.

New insights from MALDI-ToF MS, NMR, and GC-MS: mass spectrometry techniques applied to palynology.

The present study for the first time describes the application of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-ToF MS) to palynology. With an accessible mass range of up to about 350,000 Da at subpicomolar range, this technique is ideal for the characterisation of bio-macromolecules, such as sporopollenin, found in fossil and extant pollen and spore walls, which often can only be isolated in very small quantities. At this stage, the limited solubility of sporopollenin allows for the identification of sections of this biopolymer, but with the optimisation of MALDI-ToF matrices, further structure elucidation will become possible. Furthermore, gas chromatography-mass spectrometry (GC-MS) and (1)H nuclear magnetic resonance ((1)H NMR) spectroscopy data obtained from a number of experiments revealed that some previously reported data were misinterpreted. These results add support to the hypothesis that common plasticizers were wrongly described as sporopollenin compounds.

Stainless steel electrospray probe: a dead end for phosphorylated organic compounds?

A study of the interaction of phosphorylated organic compounds with the stainless components of a liquid chromatography-electrospray ionisation-mass spectrometry system (LC-ESI-MS) was carried out to disclose a (forgotten?) likely pitfall in the LC-ESI-MS analysis of phosphorylated compounds. The retention behaviour of some representative compounds of different important classes of phosphorylated biomolecules such as nucleotides, oligonucleotides, phosphopeptides, phospholipids and phosphorylated sugars was investigated during their passage through the injector and the stainless steel electrospray capillary. It became clear that the stainless steel components within the LC-ESI-MS setup were able to retain and trap phosphorylated compounds when these compounds were introduced under acidic conditions (0.1% acetic acid). Their release from these stainless steel parts was accomplished by applying an extreme basic mobile phase (25-50% ammonium hydroxide, ca. pH 12). From the data collected one could conclude that the availability of a primary phosphate group appeared imperative but was not always sufficient to realise adsorption on a stainless surface. Furthermore, the number of phosphate moieties seemed to enhance the adsorption properties of the molecules and hence roughly correlated with the analyte fraction lost. Corrosion of the inner surface caused by the mobile phase and the electrospray process was found to be an important factor in the course of these adsorption phenomena.

Urinary modified nucleosides as tumor markers.

Extracts of urinary nucleosides have been sequentially purified and examined by mass spectrometric analysis. Seventeen modified nucleosides have been unequivocally identified and a further five provisionally identified. While several nucleosides were found only in a small number of extracts, the occurrence and levels of others were found to correlate with the tumour type and stage.

Screening women for postpartum depression at well baby visits: resistance encountered and recommendations.

OBJECTIVE: Postpartum major depression afflicts 10-15% of childbearing women and can have serious consequences. Unrecognized and therefore untreated episodes of postpartum major depression can predispose women to future depressive episodes, especially those related to other reproductive events. In the United States, women typically have one visit at six weeks postpartum with their obstetrician which is focused on physical recovery from delivery. Pediatricians typically see new mothers 4-6 times per year at well baby visits. Therefore, our objective is to test the utility of screening women for postpartum depression at each well baby visit over the course of the first postpartum year as compared with controls derived from clinical practice and chart review. METHOD: Subjects for this prospective study were recruited at their first well baby visit at the UCSD Primary Care Pediatric Clinic and interviewed by telephone. Subjects then were asked to complete the Edinburgh Postnatal Depression Scale (EPDS) and the Beck Depression Inventory (BDI) at intervals consistent with the timing of well baby visits. If scores on the EPDS or the BDI exceeded the thresholds (EPDS >or= 12 and BDI >or= 10) then subjects were assessed further with the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition (SCID-DSM IV). If diagnosed with postpartum major depression, subjects were referred for appropriate treatment. RESULTS: Out of 160 study packets distributed, only 7 women volunteered for the study, despite endorsement and presentation of the study by their pediatricians. Of those participants, five scored above threshold values at some point in the interval studied. DISCUSSION: The difficulty in recruitment in this study highlights some of the problems encountered in clinical practice in terms of identifying and referring women with postpartum mental illnesses. We recommend further study be focused on how to attract potentially affected women while simultaneously addressing their fears of stigma. Since resistance also was encountered in other physicians, we recommend that educational efforts be aimed at increasing knowledge and awareness of postpartum mental illnesses in both the lay and professional spheres.

Chronobiological basis of female-specific mood disorders.

Women have twice the incidence of major depression compared with men. They are prone to develop episodes of depression during times of reproductive hormonal change at puberty, with use of oral contraceptives, during the premenstrual phase of the menstrual cycle, postpartum and during the perimenopause (see review: ). describes the variety of disturbances in biological rhythms observed in mood disorders. In this report, we describe the chronobiological disturbances observed in female-specific mood disorders, namely, premenstrual dysphoric disorder, pregnancy and postpartum depression and menopause. We hypothesize that changing reproductive hormones, by affecting the synchrony or coherence between components of the circadian system, may alter amplitude or phase (timing) relationships and thereby contribute to the development of mood disorders in predisposed individuals.

Analysis of urinary nucleosides. II. Comparison of mass spectrometric methods for the analysis of urinary nucleosides.

Qualitative and quantitative analyses of urinary nucleosides have diagnostic potential as tumour markers. We have developed separation techniques linked to mass spectrometric detection in order to overcome the problems associated with past identification and quantitation methods. The three methods of analysis utilised were: gas chromatography/mass spectrometry (GC/MS), high-performance liquid chromatography/ion-trap mass spectrometry (HPLC/ITMS) and capillary liquid chromatography/triple quadrupole mass spectrometry (CapLC/TQMS). Here we compare the relative effectiveness of each of the techniques for subsequent application in the systematic study of urinary nucleoside profiles in cancer patients. All three methods proved to be valuable techniques for such urinary nucleoside analyses, and a combination rather than one single choice is concluded as the ideal.

Analysis of urinary nucleosides. I. Optimisation of high performance liquid chromatography/electrospray mass spectrometry.

In order to optimise the analysis of urinary nucleosides by high performance liquid chromatography/mass spectrometry (HPLC/MS), the HPLC separation of these compounds was performed at different 'flow rates' and 0.2mL/min was found to give both a better separation and ionisation. The ionisation conditions were optimised to give the best intensity of the molecules quasi-molecular ions. The ion distribution profile and ionisation in both positive and negative mode were examined and the detection of the protonated molecule in positive mode chosen for further analysis. The limits of detection of the method developed are reported and representative LC/MS and LC/MS/MS spectra shown. Typical urinary nucleoside chromatograms are presented.

Development of a purification procedure for the isolation of nucleosides from urine prior to mass spectrometric analysis.

A chromatographic separation of nucleosides from urine has been developed in order to facilitate their mass spectrometric analysis for clinical diagnosis. A number of chromatographic resins were studied in order to develop an effective and efficient purification procedure. The optimized sequential protocol comprises a centrifugation, acidification and neutralization step, followed by application of an affinity chromatographic column and finally further separation on an acidic cation exchange column and a basic anion exchanger. This scheme shows effective clean-up of a standard radiolabelled nucleoside with a recovery of 92.5%, and recovery of nucleosides added to urine samples before extraction showed recoveries of 72-82%.

Identification, purification and properties of a beta-1,3-glucan-specific lectin from the serum of the cockroach, Blaberus discoidalis which is implicated in immune defence reactions.

A lectin specific for laminarin, a beta-1,3-glucan, agglutinating baker's yeast and enhancing prophenoloxidase activation by laminarin, has been purified from the cockroach, Blaberus discoidalis, serum. Purification involved gel filtration with Bio-gel P300 and affinity chromatography on blue Sepharose CL-6B and laminarin-Sepharose 4B. The purified lectin has a molecular mass estimate of 520 kDa determined by gel filtration, and approximately 80 and 82 kDa by SDS-PAGE, under non-reducing and reducing conditions, respectively. After isoelectric focusing the lectin focused as a single band at pH 4.9. The purified lectin was stained by the periodic acid/Schiff's reagent showing that it is a glycoprotein, and was deglycosylated by endo-beta-N-acetylglu-cosaminidase F. Amino acid composition analysis showed the protein is similar to previously purified beta-1,3-glucan binding proteins from other invertebrates. In electron micrographs by negative staining, the protein formed large aggregates with 'Y'-shaped 'structural units' ca. 79 x 65 nm. Immunological tests confirmed that this lectin is not related to any other lectins previously purified from the same insect. This protein appears to be part of the hexamerin family of proteins. This is one of the first reports of a hexamerin-like molecule with lectin activity.

Kinetic analysis of cyclic CMP-specific and multifunctional phosphodiesterases by quantitative positive-ion fast-atom bombardment mass spectrometry.

Two enzymes, cyclic CMP-specific phosphodiesterase and multifunctional phosphodiesterase, are responsible for the hydrolysis of cytidine 3',5'-cyclic monophosphate in living cells. Quantitation of both enzymes has been carried out by positive-ion fast-atom bombardment mass spectrometric analysis of the enzyme incubates after termination of the reaction. The kinetic data obtained are in close agreement with parallel data obtained by the conventional radiometric assay. The extra facility of the mass spectrometry based assay to monitor several incubation components simultaneously has been exploited to study the concurrent hydrolysis of alternate cyclic nucleotide substrates and provides kinetic parameters of significance in interpreting substrate-enzyme interactions. This is extended by the use of collisionally-induced dissociation of the protonated molecules of the liberated products to identify the mononucleotide isomers resulting from the cyclic nucleotide hydrolysis.

Studies on a haemolymph lectin isolated from Rhodnius prolixus and its interaction with Trypanosoma rangeli.

We demonstrated that in Rhodnius prolixus haemocyte monolayers, both Trypanosoma cruzi and Trypanosoma rangeli are capable of inducing haemocyte/parasite clump formation. We also purified, by one-step affinity chromatography, a haemolymph galactoside-binding lectin from R. prolixus which we believe could play an important role in the development of T. rangeli in the haemocoel of the insect vector. This lectin markedly enhanced the activation of clump formation by T. rangeli in R. prolixus haemocyte monolayers, with an increase in clump size and haemocyte aggregation. The haemolymph lectin also significantly affected the motilitity and survival of T. rangeli culture short forms, but not the long forms, when they were incubated in vitro. This molecule is also one of the few described in insects with agglutination activity independent of calcium ions. The partial N-terminal amino acid sequence of this lectin demonstrated similarity to a bacterial xylulose kinase and in preliminary experiments the purified haemolymph lectin phosphorylated a tyrosine kinase substrate in a dose-dependent manner. The possible role of this haemolymph lectin in the life cycle of T. rangeli is discussed.

Fast-atom bombardment tandem mass spectrometry of cyclic nucleotide analogues used as site-selective activators of cyclic nucleotide-dependent protein kinases.

The mass spectrometric behaviour of six cyclic nucleotide analogues which activate cyclic AMP-dependent protein kinase was studied by positive-ion fast-atom bombardment (FAB) and collision-induced dissociation (CID) mass-analysed ion kinetic energy (MIKE) spectrometry. The compounds studied were 1,N6-ethenoadenosine-3',5'-cyclic monophosphate, (epsilon-cyclic AMP) and 2'-aza-1,N6-ethenoadenosine-3',5'-cyclic monophosphate, which each activate both isoforms of cyclic AMP-dependent protein kinase and have similar affinity for both the 'fast' and the 'slow' regulatory site of each isoform, N6-phenyl-cyclic AMP, which is selective for the 'fast' regulatory site of each isoform, and 6-chloropurine riboside-3',5'-cyclic monophosphate, 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole-3',5'-cyclic monophosphate and 8-(4-chlorophenylthio)-adenosine-3',5'-cyclic monophosphate, which are each selective for the 'slow' regulatory site and preferentially activate isoform II. The FAB- and CID/MIKE spectra of the analogues are discussed in relation to their use in studies of the regulation of protein kinase activity by quantitative FAB mass spectrometry.

Kinetic analysis and multiple component monitoring of effectors of adenylyl cyclase activity by quantitative fast-atom bombardment mass spectrometry.

The enzyme adenylyl cyclase catalyses the conversion of adenosine 5'-triphosphate (ATP) to adenosine-3',5'-cyclic monophosphate (cyclic AMP), and is an important pharmaceutical target. Quantitation of this enzyme's activity has been carried out by positive-ion fast-atom bombardment mass spectrometric analysis of the enzyme incubation mixture after the reaction has been terminated. The kinetic data obtained are in good agreement with those obtained by the conventional radiometric assay, and this mass spectrometry-based assay offers the facility to monitor the turnover of several components of the incubation simultaneously. This is utilized to study the relative efficiencies of two ATP-regenerating systems, three phosphodiesterase inhibitors and two modified substrates, and to monitor the uptake and conversion of two competing substrates, adenosine 5' triphosphate and 2'-deoxyadenosine-5-triphosphate, to cyclic AMP and to cyclic deoxyAMP, respectively.