bluuebunny/crossref_metadata_2025 huggingface dataset:
High resolution 1H and 13C NMR and mass spectral studies of substituted dipyridylpyridazine
Authors: El-Qisairi Arab K.
Published: March 2012

Total assignment of the 1H and 13C NMR spectra of 3,6‐bis(2′‐pyridyl)pyridazine derivatives (n‐dppn) have been recorded at 400 and 100 MHz, respectively.1Based on these data, the complete assignment of the 13C NMR chemical shift
values was made by a 13C{1H} decoupling. The spectra clearly show that the n‐dppn ligands exist in the cis–cis conformation at least in solution. Matrix assisted laser desorption ionization (MALDI) and time‐of‐flight mass spectrometry (TOFMS) are used
to record the mass spectra of the n‐dppn ligands. α‐Cyano‐4‐hydroxycinnamic acid (CHCA) matrix promoted the molecular
ion detection when 180 pmol of n‐dppn is introduced into the TOFMS.
Sulphur K‐edge XANES Spectroscopy of Transthyretin Amyloid Fibres
Authors: Gales L. , Cardoso I. , Fayard B. , Saraiva M.J. , Damas A.M.
Published: March 2012

Transthyretin (TTR) amyloidosis results from the self‐association of TTR leading to insoluble deposits that occur at the extra cellular level. Sulphur K‐edge XANES spectroscopy was used to determine the sulphur oxidation state in transtyretin present in amyloid fibrils. These data is discussed in relation to molecular mechanisms involved in amyloid fibril formation.
Infrared spectra of some fructans
Authors: Grube M. , Bekers M. , Upite D. , Kaminska E.
Published: March 2012

The FT–IR spectra of fructan – inulin (RAFTILINE), widely applied in the food industry and crystalline fructose as the main component of fructans, were studied. Special interest was to study the spectra of the levan precipitate and fructan syrup – produced by Zymomonas mobilis during the fermentation on sucrose–based medium.

It was shown that levan precipitate and fructose syrup does not contain lipids and nucleic acids. Levan precipitate consists of ∼93% of fructose and admixture of glucose, mannan and enzyme – levansucrase. Fructan polymer inulin consists principally of linear chains of fructosyl units linked by a β(2–1) bonds ended by a glycosyl unit. The links between the molecules are of a very special type: the β(2–1) form (2) [8]. The bacterial fructans of the levan type are high molecular weight polymers, i.e., they are composed ofβ–(2,6)–ructosyl–fructose linked molecules and side chains [17]. The FT–IR spectra of levan, apart from inulin’s, in the carbohydrate region 900–1200 cm–1, shows overlapping broad band with maximum at ∼1030 cm–1 and stronger absorption at ∼940 cm–1. The differences in both spectra could be caused by different structure and glucose, sucrose and mannan influence.
Recent results on biomedical problems: A Fourier transform infrared (FT‒IR) study
Authors: Crupi V. , Galli S. , Majolino D. , Migliardo P. , Pergolizzi S. , Venuti V.
Published: March 2012

In the present work, we report on a vibrational study performed on rat encephalon samples and on human tissue affected by cancer, using Fourier Transform Infrared absorbance spectroscopy. As the brain rat tissue is concerned, the FT‐IR measurements, performed in the CH–OH vibrational stretching region (2400–3800 cm−1), permitted us to reveal the presence of a very diffuse commercial benzodiazepine: VALIUM® . The comparison between the spectral features of normal brain and the ones of samples with administrated substance has unambiguously showed that the CH stretching region seems not to be affected by any change for the pharmacological treatment, instead the OH band is strongly modified probably due to the presence of a new spectral contribution characteristic of diazepam molecule. In the case of skin tissue the investigation was addressed to characterize the presence of two different pathologies, namely epithelioma and basalioma, and to show clear different spectral features passing from the normal tissue to the malignant one in particular in the region (1500–2000 cm−1) which is typical of the lipids vibrational bands.
The interaction between captured human thrombin and antithrombin studied by surface plasmon resonance, and the effect of melagatran
Authors: Elg Susanne , Deinum Johanna
Published: March 2012

The kinetics of the interactions between thrombin and antithrombin were studied by surface plasmon resonance. Although amine coupled thrombin binds low molecular weight active site inhibitors with a one‐to‐one stoichiometry hirudin only bound to 75% of the coupled active thrombin. However, antithrombin or thrombomodulin could not bind at all to amine‐coupled thrombin. To make it possible to follow the reaction with antithrombin in time thrombin was therefore captured on an antibody against thrombin. Alternatively, antithrombin was captured on an antibody against antithrombin to follow complex formation with thrombin. With these techniques the second‐order rate constant for the interaction of antithrombin with thrombin in the presence of heparin, was estimated to be ka≥0.4×106 M−1 s−1 with KD═ 50 nM for the formation of the initial complex. These values are similar to those found in solution. In the absence of heparin, the second‐order rate constant for the interaction of thrombin with captured antithrombin was only ka ═ 9×103 M−1 s−1. Thus, with this technique rate constants for the interaction of proteases with serpins can be determined in a convenient way, without the need for stopped‐flow. The rapid‒binding, active‐site‐directed thrombin inhibitor, melagatran, competed with the antithrombin‐thrombin interaction. Although melagatran, a reversible thrombin inhibitor, initially prevented formation of the complex, ultimately the irreversible thrombin‐antithrombin complex was always formed.
Analysis of Binding Affinity of Sugars to Concanavalin A by Surface Plasmon Resonance Sensor BIACORE
Authors: Goto Satoru , Terada Hiroshi
Published: March 2012

The observed dissociation constant kd of the lectin concanavalin A (ConA) from glycoprotein asialofetuin (ASF) changed with the concentration of inhibitory sugars. The reciprocal of kd showed a linear relationship with the reciprocal of sugar concentration. This regression line was found to be theoretically available in the analysis of the kinetics in the interaction of sugars with ConA under conditions where the binding constant Ki of sugars to ConA is more than about 333.
Surface‒functionalized, probe‒containing, polymeric nanospheres for biomedical imaging
Authors: Thomas Rhys N. , Guo Congyuan
Published: March 2012

Nanoparticles may be bound covalently to biological macromolecules for imaging, reporting, or delivery of therapeutic agents. The nanospheres of this report range from 15 nm to 30 nm in diameter, depending on the composition, although each type of nanosphere varies only ±5 nm from its mean. These nanospheres are smaller than an antibody, so may be used in the same way as other antibody labels such as enzymes in immunoassay. A double micelle forms the core of these nanospheres, in which a water pool contains approximately 1200 ionic probes such as fluorescent lanthanides, ferrite, borohydrides for BNCT, or hydrophilic therapeutic agents. Stability is imparted to the double micelle by a polymeric net that is woven into the hydrophobic zone, allowing control of diffusion. Imagable atoms may be incorporated as monomers into this polymeric net, providing as many as 200,000 fluorine atoms for 19F MRI or 40,000 iodide atoms for CAT. The surfaces of the nanospheres may be tailored with hundreds of active groups such as acids or amines for later conjugation, and also polar groups such as esters, alcohols, and amino acids to suit the intended environment. The finished nanospheres may be conjugated to macromolecules using rapid, simple reactions.
Temperature Induced Conformational Transitions of Elastin‐Like Polypentapeptides Studied by Raman and NMR Spectroscopy
Authors: Dybal Jirí , Schmidt Pavel , Kurková Dana , Kríž Jaroslav , Rodríguez-Cabello José Carlos , Alonso Matilde
Published: March 2012

Raman and NMR spectroscopy together with DFT quantum chemical calculations have been used to elucidate conformational changes occurring during inverse temperature transition in water solution of two elastin‐like polypentapeptides, poly(G1V1G2V2P) and poly(AV1GV2P). From the temperature dependences of Raman spectra and 1H–1H NOESY spectra follows that above the transition temperature a β(II)‐turn conformational structure is formed on the residue located between Pro and Val1.
Quantification of urine 17‐ketosteroid sulfates and their age correlations
Authors: Jia Qi , Hong Mei-Feng , Pan Zhao-Xing , Ritter Cheryl , Vance Susan , Cortes-Guzman Miriam , Cherniske Stephen
Published: March 2012

Dehydroepiandrosterone (DHEA) is a steroid secreted primarily by the adrenal gland and plays an important role as the primary precursor of many important sex steroids. The negative correlation between age and the secretion of DHEA (I) and in its sulfate form (II, DHEA‐S) has been documented in human studies. Serum DHEA (I) and/or DHEA‐S (II) levels have been associated with central nervous system function, immunity, cardiovascular functions, insulin sensitivity, and body composition.

A high‐performance liquid chromatography/ion trap mass spectroscopic method with sonic spray ionization (SSI) for the quantification of individual and total urinary 17‐ketosteroid sulfates was developed. This quantification method had broad linearity range, low detection limit and high throughput. The amount of 17‐KS‐S, normalized by creatinine, in urine secreted over 24 hours versus that in early morning urines was found inversely correlated to age for both genders.
The role of clinical in vivo 1H–MR spectroscopy in the evaluation of epilepsies
Authors: Hammen T. , Stefan H. , Tomandl B.
Published: March 2012

1H–MRS which is a noninvasive method in detecting various brain metabolites containing N–acetylaspartat (NAA), cholin (Cho), creatin (Cr) GABA and glutamat has become a diagnostic tool for assessing a number of diseases of the central nervous system particularly including epilepsies and brain tumours. 1H–MRS plays an increasing role in the evaluation of epilepsies and their treatment schedules today. NAA is accepted as a marker of neuronal/axonal density and viability. It’s detailed physiological role is yet unknown. A loss or decrease of NAA is seen in diseases which are associated with loss of neurons or axonal degeneration. GABA, glutamate and glutamin (Glx) probably define the epileptic focus in biochemical terms. 1H–MRS implies high sensitivity and validity in focus localization in patients with temporal lobe epilepsies (TLE) compared to established methods like video EEG, MR–volumetry and SPECT. In patients with intractable mesial TLE who were scheduled for surgery NAA/Cr or NAA/Cr + Cho asymmetry indexes of the hippocampal formation were created and compared to healty controls. The results were related to the mentioned already established localization techniques. Most authors which investigated this topic likewise found that 1H–MRS is highly concordant to EEG and MRI–Vol findings. Recent studies show that 1H–MRS besides it′s capability to lateralize the epileptic focus is able to distinguish between mesial and lateral TLE. In addition to it′s sensitivity in focus lateralization 1H–MRS contains a predictability concerning the evaluation of postoperative outcome in patients with intractable TLE. Most studies reveal that changes contralateral to the epileptogenic focus or bilateral changes in metabolite spectra of 1H–MRS are associated with a poor whereas homolateral alterations to the focus reveal a good postoperative seizure outcome. The evaluation of anticonvulsive drugs by 1H–MRS is the topic of various recent studies in which human brain GABA levels are investigated by 1–HMRS under the influence of antiepileptic drugs mainly including vigabatrin and topiramat. The effect of antiepileptic drugs and their influence on seizure inhibitoring brain metabolites was investigated and the authors were able to create responder profiles by correlating the mentioned metabolites in a long–term study. They verified an increase of GABA within the beginning of antiepileptic treatment and an increase of homocarnosine, a GABA metabolite, in long term treatment (2–3 months) in the responder group.
Analysis of Protein Folding Equilibria by Nano‐Electrospray‐Ionization Mass Spectrometry
Authors: Matecko Irena , Müller Norbert , Grandori Rita
Published: March 2012

This paper summarizes recent findings from our group concerning applications of electrospray‐ionization mass spectrometry (ESI‐MS) to the study of protein folding. Nano‐ESI‐MS was employed for the investigation of protein conformational states under varying solvent conditions and at varying values of the instrumental parameters. The effect of trifluoroethanol (TFE) on a peptide and acid‐unfolded cytochrome c (cyt c), monitored by circular dichroism (CD) and time‐of‐flight ESI‐MS, illustrates the specificity of the latter technique for features of protein tertiary structure. Measurements on marginally stable protein states indicate that it is possible to identify operational conditions for nano‐ESI‐MS in which none of the instrumental parameters limits conformational stability in the protein sample. Results described here show that changes in the charge‐state distributions (CSDs) under controlled conditions allow not only discriminating between native and denatured states, but also monitoring minor conformational changes, like the transition from molten globule to native state. These studies underscore the potential of mass spectrometry methods for the analysis of heterogeneous samples and, in particular, for the characterization of dynamic equilibria involving different conformational states.
Two‐dimensional infrared correlation spectroscopy studies on secondary structures and hydrogen bondings of side chains of proteins
Authors: Ozaki Yukihiro , Murayama Koichi , Wu Yuqing , Czarnik-Matusewicz Bogusława
Published: March 2012

This review paper reports usefulness of two‐dimensional (2D) correlation spectroscopy in analyzing infrared (IR) spectra of proteins in aqueous solutions. In the 2D approach, spectral peaks are spread over the second dimension, thereby simplifying the visualization of complex spectra consisting of many overlapped bands, and enhancing spectral resolution. 2D correlation spectroscopy has a powerful deconvolution ability for highly overlapped amide I, amide II, and amide III bands of proteins, enabling these bands to be assigned to various secondary structures. It also provides the specific order of the spectral intensity changes taking place during the measurement on the value of controlling variable affecting the spectra. Therefore, one can monitor the order of secondary structure variations in proteins by using 2D IR correlation spectroscopy. 2D correlation spectroscopy also provides new insight into the hydrogen bondings of side chains of proteins. In this review the principles and advantages of 2D correlation spectroscopy are outlined first and then three examples of the applications of 2D IR spectroscopy to protein research are presented.
A rapid spectrophotometric method for the determination of mercury in environmental, biological, soil and plant samples using diphenylthiocarbazone
Authors: Ahmed M. Jamaluddin , Alam Md. Shah
Published: March 2012

A simple, sensitive and highly selective direct spectrophotometric method for the determination of trace levels of mercury(II) in various samples is described. Diphenylthiocarbazone (dithizone) reacts in slightly acidic 50% aqueous 1,4‐dioxane media (0.18–1.80 M sulphuric acid) with mercury(II) to give an orange chelate which has an absorption maximum at 488 nm. The average molar absorption co‐efficient and Sandell′s sensitivity were found to be 2.5×104l mol−1 cm−1 and 0.015 μg of Hg(II) cm−2, respectively. The reaction is immediate and absorbance remains stable for over 24 h. Beer′s law is obeyed for concentration range of mercury(II) between 0.1 μg ml−1 and 25 μg ml−1; the stoichiometric composition of the chelate is 1 :2 (mercury : dithizone). The various analytical parameters, such as effect of time, acidity, reagent concentration and foreign species, were studied. The method was applied successfully to a number of environmental waters (portable and polluted), biological samples (human blood, urine and fish), soils, plant samples (potato, cabbage, lettuce, carrot and tomato), solutions containing both mercury(I) and mercury(II) and complex synthetic mixtures. The method is very simple and requires no solvent extraction or pre‐concentration steps.
Structural Characterization of the C2 Domains of Classical Isozymes of Protein Kinase C and Novel Protein Kinase Cε by using Infrared Spectroscopy
Authors: Corbalán-García Senena , García-García Josefa , Sánchez-Carrillo M. Susana , Gómez-Fernández Juan C.
Published: March 2012

The amide I regions in the original infrared spectra of PKCα‐C2 in the Ca2+‐free and Ca2+‐bound states are both consistent with a predominantly β‐sheet secondary structure. Spectroscopic studies of the thermal denaturation revealed that for the PKCα‐C2 domain alone the secondary structure abruptly changed at 50°C. While in the presence of Ca2+, the thermal stability of the protein increased considerably. Phosphatidic acid binding to the PKCα‐C2 domain was characterized, and the lipid–protein binding becoming Ca2+‐independent when 100 mol% phosphatidic acid vesicles was used. The effect of lipid binding on secondary structure and thermal stability was also studied. In addition, the secondary structure of the C2 domain from the novel PKCε was also determined by IR spectroscopy and β‐sheet was seen to be the major structural component. Spectroscopic studies of the thermal denaturation in D2O showed a broadening in the amide I′ band starting at 45°C. Phosphatidic acid containing vesicles were used to characterize the effect of lipid binding on the secondary structure. It was observed through thermal stability experiments that the secondary structure did not change upon lipid binding and the protein stability was very high with no significant changes occurring in the secondary structure after heating.
Calibration and Standardisation of Synchrotron Radiation Circular Dichroism and Conventional Circular Dichroism Spectrophotometers
Authors: Miles Andrew J. , Wien Frank , Lees Jonathan G. , Rodger A. , Janes Robert W. , Wallace B. A.
Published: March 2012

Synchrotron radiation circular dichroism (SRCD) is an emerging technique in structural biology with particular value in protein secondary structure analyses since it permits the collection of data down to much lower wavelengths than conventional circular dichroism (cCD) instruments. Reference database spectra collected on different SRCD instruments in the future as well as current reference datasets derived from cCD spectra must be compatible. Therefore there is a need for standardization of calibration methods to ensure quality control. In this study, magnitude and optical rotation measurements on four cCD and three SRCD instruments were compared at 192.5, 219, 290 and 490 nm. At high wavelengths, all gave comparable results, however, at the lower wavelengths, some variations were observable. The consequences of these differences on the spectrum, and the calculated secondary structure, of a representative protein (myoglobin) are demonstrated. A method is proposed for standardising spectra obtained on any CD instrument, conventional or synchrotron‒based, with respect to existing and future databases.
Superposition of chemical shifts in NMR spectra can be overcome to determine automatically the structure of a protein
Authors: Auguin D. , Catherinot V. , Malliavin T. E. , Pons J. L. , Delsuc M. A.
Published: March 2012

We are here addressing the problem of the automatic determination of a protein structure at atomic resolution, by using only the signal recorded on three spectra: 2D 15N HSQC, 3D 15N NOESY‐HSQC and TOCSY‐HSQC. A modified version of the neural network RESCUE (J.L. Pons and M.A. Delsuc, J. Biomol. NMR 15 (1999), 15−26), N15‐RESCUE, is developed in order to predict the amino‐acid type from only the 15N, HN, Hα and Hβ chemical shifts. The spatial distances between protein residues are estimated by automatic comparison of columns extracted from a 3D 15N NOESY‐HSQC spectrum, using the FIRE method (T.E. Malliavin, P. Barthe and M.A. Delsuc, Theor. Chem. Accts 106 (2001), 91−97). The predictions provided by both FIRE and N15‐RESCUE methods are then used for the determination of a preliminary NMR structure of the protein p8. A mean RMSD value of 2.31±0.86 Å is observed between the coordinates of heavy atoms from helices αI and αII, and the αIII helix is taking random orientations with respect to the other helices. This random orientation is a consequence of the lack of predicted proximities between αIII and αII, and is in agreement with other independent observations made on p8 structure.
Fourier Transform Infrared Spectroscopic Studies of Diabetic Rat Heart Crude Membranes
Authors: Severcan Feride , Kaptan Neşe , Turan Belma
Published: March 2012

Application of mid infrared spectroscopy in diabetic tissues will be presented which highlight the promise of this technique in medical research. Examples presented mainly will focus on diabetic rat heart crude membranes. Diabetes mellitus (DM) was induced in rats by streptozotocin (STZ) injection that is one of the most popular experimental models for the study of type I diabetes. The shift in the peak positions, bandwidths and the intensity of the bands in FTIR spectra were analyzed to have valuable structural and functional information, which may have diagnostic value. In the diabetic membranes significant increase was observed in lipid order and lipids concentration. While the concentration of saturated lipids increases, the concentration of unsaturated lipids decreases. In addition, broadening of the amide I bands and the appearance of the new band around 1640 cm−1 together with the decrease in the amide I to amide II ratio indicate the structural changes occurring in proteins of diabetic membranes. A dramatic increase in oligosaccarite band (1042 cm−1) and a decrease in olefinic stretching band (3012 cm−1), were also observed.
Chemical Characterization of a New Carbohydrate Metabolite in the Vitreous of Black Moor Goldfish by Liquid Chromatography‐Electrospray Mass Spectrometry and Nuclear Magnetic Resonance
Authors: Zhou Lei , Juneau Gary , Xiong Xiang , Lai Helen W. L. , Yew David T. , Lam Kwok-Wai
Published: March 2012

Our recent report has described the occurrence of a remarkably high amount of an unknown compound with light absorption maximum at 290 nm in the aqueous humor of Black Moor goldfish. The absorption maximum is shifted to 270 nm in 0.01% trifluroacetic acid. The concentration of this compound was very low in the eye of common goldfish and was absent in ocular fluids or serum of mammalian species. This compound was isolated by chromatography on a carbohydrate column eluted by 10 mM ammonium phosphate followed by chromatography on a Delta PAK C18 column eluted by acetonitrile–water–trifluoroacetic acid. The ion size of the unknown compound determined by electrospray for protonated and deprotonated ions are m/z 205 and 203, respectively. The protonated ion was fragmented to m/z 187, 169, 157 and 141 as the cone voltage increased. The data from mass spectrometry and nuclear magnetic resonance spectroscopy indicate the chemical structure of a carbohydrate with 7 carbons containing a lactone ring.
Simultaneous pO2 and HbO2 measurement to determine absolute HbO2 concentration for in vivo near infrared spectroscopy
Authors: Macnab Andrew J. , Gagnon Roy , Gagnon Faith , Minchinton Andrew I. , Fryer Karen H.
Published: March 2012

Purpose: Near infrared spectroscopy (NIRS) monitors absolute changes in concentration of chromophores from an unquantified baseline. A change in oxygenation is required to obtain information. Clinically, knowing initial chromophore concentration is desirable. We sought absolute initial concentrations by combining NIRS measurements with simultaneous Eppendorf histograph measurement (absolute values of tissue partial pressure of oxygen (pO2)). Methods: There were 22 trials on 9 occasions in 2 adult volunteers. Following local anaesthetic, the histograph probe was inserted into the forearm muscle and NIRS optodes applied. A sphygmomanometer cuff was inflated over the upper arm to produce ischaemia and hypoxia. Change in pO2 was determined as a percentage of the initial pO2. Change in HbO2 was measured, and the initial HbO2 calculated by assuming the percentage change in HbO2 equaled the percentage change in pO2. Results: Mean percentage change in pO2 was 20.7 ± 9.6. Mean change in HbO2 was 22.4 ± 3.4 µmol/l(tissue). Calculated initial HbO2 was 146.4 ± 108.7 µmol/l(tissue), range 51 to 508 µmol/l(tissue). Correlation (r2) between pO2 and HbO2 was 0.97 ± 0.03. Conclusion: Although changes in pO2 and HbO2 were highly correlated, calculation of initial absolute concentration of HbO2 was not achieved by this method. A reliable method of obtaining absolute concentrations of HbO2in vivo remains to be found.
Adding a New Spectral Dimension to Localized 1H MR Spectroscopy of Human Prostates using an Endorectal Coil
Authors: Thomas M. Albert , Binesh Nader , Yue Kenneth , Banakar Shida , Wyckoff Nathaniel , Huda Amir , Marumoto Alan , Raman Steve
Published: March 2012

Localized 2D shift‐correlated MR spectra (L‐COSY) of human prostates were recorded using an endorectal “receive” coil. Typically, 4 ml voxels were placed in the peripheral zones of the prostate. Seven healthy volunteers and one BPH patient have participated in this study so far. The total acquisition time for a 2D L‐COSY was approximately 20 minutes. A 1.5 Tesla GE scanner with a body coil for RF transmission and a pelvic phased‐array coil combined with a disposable rectal coil for reception was used. The 2D L‐COSY spectra showed cross peaks due to citrate, spermine and occasionally choline, creatine and lipids. The 2D cross peaks due to both the multiplets of spermine were clearly resolved from choline and creatine which has been a major problem with the conventional MR spectroscopic techniques. In contrast to 2D JPRESS, improved spectral dispersion, less crowded 2D cross peaks and unequivocal detection of both multiplets of spermine were monitored in 2D L‐COSY. Pilot results suggest that localized 2D L‐COSY can be successfully implemented in human prostates on a clinical scanner.
High‐throughput cassette assay for drug stability measurement in plasma using direct HPLC‐MS/MS
Authors: Wang Gangfeng , Hsieh Yunsheng , Cheng K.-C. , Ng Kwokei , Korfmacher Walter A.
Published: March 2012

A high‐throughput semi‐automated procedure for simultaneously stability evaluation of multiple compounds in plasma using direct single column high‐performance liquid chromatography (HPLC) combined with tandem mass spectrometry (MS/MS) was developed to eliminate the laborious procedures that are traditionally used for stability studies. Untreated human, monkey, mouse and rat plasma samples containing ten drug components were directly injected into a mixed‐functional column that provided both protein removal and chromatographic functionality. Ten test compounds were simultaneously assayed using a tandem mass spectrometer in the positive ion mode using multiple reaction monitoring (MRM). Plasma samples containing ten test compounds were placed in a thermostatic autosampler and then sequentially monitored in one analytical procedure. The time between each injection was set about 7 minutes. The peak responses of the test compounds in individual plasma samples were repeatedly determined every 28 minutes. Drug stability in plasma was indicated by the change of the mass chromatographic peak areas for the test compounds and was observed to be a function of animal species, incubation time and incubation temperature. The potential for matrix ionization suppression on the direct single column HPLC‐MS/MS system was also investigated using the post‐column infusion technique. The proposed cassette assay procedure provides an analytical throughput ten times greater than the single component approach for the evaluation of drug stability in plasma without compromising data quality.
Electron paramagnetic resonance spectroscopic studies of iron and copper proteins
Authors: Taiwo Fatai A.
Published: March 2012

Transition metal (d‐group) ions are widespread in nature, essential for structural characteristics and mechanistic specificity of many proteins. Iron and copper are the two most prevalent metals in proteins responsible for the storage and transport of molecules, ions, and electrons. Electron paramagnetic resonance (EPR) spectroscopy has been extensively used for the determination of these metal ions without extensive disruption of the native protein moiety. It also detects variations in coordination geometry due to ligand substitutions as well as multiple valencies of the same metal. This review highlights the unique application of EPR spectroscopy to the study of iron and copper in biological systems. Mention is made of a select number of other metalloproteins.
Application of Multiple NIRS Imaging Device to the Exercising Muscle Metabolism
Authors: Miura Hajime , McCully Kevin , Chance Britton
Published: March 2012

Near infrared spectroscopy (NIRS) is a developing technique that measures the balance between muscle oxygen consumption and oxygen supply that is noninvasive and potentially portable. Differential absorption of light in the 600−900 nm region detects the changes in small vessel hemoglobin oxygen saturation and blood volume. Recent developments include the combining of multiple light sources and photodetectors to provide “images” of oxygen saturation and blood volume of wide regions of muscle. Using multiple NIRS imaging device, we monitored localized muscle metabolism during various exercises in the field as well as in the laboratory. In healthy subjects, the regional differences in oxygen saturation and blood volume were detected in the medial head of the gastrocnemius muscle during a standing plantar flexion exercise, consistent with differences in intramuscular pressure. Patients with peripheral arterial disease (PAD) showed slower recovery for both oxygenation and blood volume after exercise. Treatment for PAD resulted in improvements in NIRS‐measured recovery times. In summary, NIRS devices have the ability to detect and monitor impaired muscle circulation. In addition, NIRS devices with multiple channels have the potential to evaluate the regional differences in oxygen status. Multiple NIRS imaging devices have the potential to play an important role in monitoring exercise prescription and clinical uses.
A novel and rapid approach to yeast differentiation using matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry
Authors: Sherburn Richard E. , Jenkins Richard O.
Published: March 2012

Matrix‐assisted laser desorption/ionisation time of flight mass spectrometry (MALDI‐TOF‐MS) was investigated as a method for the rapid identification of yeast cells. Following pretreatment of yeast samples with a cell wall digesting enzyme (lyticase), distinct and reproducible mass spectra over the m/z range 2,000 to 16,000 were obtained by MALDI‐TOF‐MS. Using an optimised procedure, characteristic mass spectra that distinguished between Candida spp. and between strains of Saccharomyces cerevisiae were produced. The approach offers the potential for rapid differentiation of yeasts in clinical diagnosis and in the fermentation industries.
Application of FTIR and Raman Spectroscopy to Characterisation of Bioactive Materials and Living Cells
Authors: Notingher I. , Jones J. R. , Verrier S. , Bisson I. , Embanga P. , Edwards P. , Polak J. M. , Hench L. L.
Published: March 2012

Both Fourier Transform Infrared (FTIR) and Raman spectroscopy have been applied to the in vitro characterisation of biomaterials, mainly surface reactions leading to the formation of a biologically active hydroxycarbonate apatite (HCA) layer on the sample surface when immersed in simulated body fluids (SBF). The HCA layer indicates the degree of bioactivity of the sample, because it leads to a strong bond between the biomaterial and living tissue. Reflection measurements using FTIR allow quick, non‐destructive detection of the HCA layer for solid and powder samples. Due to the low Raman scattering efficiency and low absorption of water in the visible‐near infrared region, Raman micro‐spectroscopy was successfully used for the in situcharacterisation of 20 and 40 µm diameter 45S5 Bioglass® fibres. The in situ capabilities of the Raman micro‐spectrometer have also been extended to the characterisation of living cells attached on bioinert silica and bioactive 45S5 Bioglass® and 58S substrates. Using a high power 785 nm laser, living cells in physiological conditions can be real‐time sampled over long periods of time without inducing cell damage and with good signal strength. Cell death can be monitored because it proved to induce strong changes in the Raman signature in the spectral regions 1000–1150 cm–1 and 1550–1650 cm–1.
Biosensors based on nucleic acid interaction
Authors: Minunni M.
Published: March 2012

DNA sensing is an emerging technology based on hybridisation reaction between an immobilised DNA probe and a molecular target, consisting of a probe complementary sequence in solution. Many application have been developed in the field of environmental, food and clinical analysis.

Surface plasmon resonance and piezoelectric sensing are reported as transduction principles for DNA‐based devices. These techniques are able to monitor in real‐time and without the use of any label the hybridisation reaction between nucleic acids. Particular attention is given to Genetically Modified Organism detection.
Microspectroscopic investigation of malignant cells from cell culture and leukemic patients
Authors: Huleihel Mahmoud , Salman Ahmad , Talyshinsky Marina , Souprun Yelena , Erukhimovitch Vitaly
Published: March 2012

In the present study we used microscopic Fourier‒Transform Infrared spectroscopy (FTIR) to investigate and to detect malignant cells which were transformed in culture by murine sarcoma virus (MuSV) or obtained from human leukemic patients. The advantage of microscopic FTIR spectroscopy over conventional FTIR spectroscopy is that it facilitates inspection of restricted regions of cell culture or the tissue. Our results showed significant and consistent differences between the various tested normal cells (primary cells and cell lines obtained from different origins) and malignant cells either transformed by MuSV or obtained from human leukemic patients. A considerable decrease in carbohydrates and phosphates levels was seen in malignant cells compared to the normal cells. In addition, the peak attributed to the PO2− symmetric stretching mode at 1082 cm−1 in normal cells was shifted significantly to 1087 in malignant cells. Furthermore, treatment of the leukemic patients with appropriate chemotherapy could be detected easily by FTIR spectroscopy; the spectral absorbance of the cells from the treated leukemic patients became very similar to normal lymphocytes. These results in addition to further differences in the shapes of various bands throughout the spectrum strongly support the possibility of developing the FTIR microscopy for the detection and study of malignant cells and probably as indication for successful treatment.
Biodistribution and biocompatibility investigation in magnetoliposome treated mice
Authors: Lacava Z. G. M. , Garcia V. A. P. , Lacava L. M. , Azevedo R. B. , Silva O. , Pelegrini F. , De Cuyper M. , Morais P. C.
Published: March 2012

Magnetoliposomes (ML′s) may be successfully applied for several purposes. A dimyristoylphosphatidyl‒choline‒based ML (ML‒2) sample was developed as a precursor of more complex thermal cancer therapy systems. The present study reports on morphology and magnetic resonance (MR) investigations carried out with the magnetite‒based ML‒2 sample. For the experiments, adult female Swiss mice were endovenously treated with a bolus dose of 100 µl of ML‒2. Morphology and room‒temperature MR studies (X‒band experiments) were performed in several organs collected from 1 hour to 28 days after ML administration. Histological data showed magnetic nanoparticle (MNP) clusters up to the 28th day in the liver and spleen tissues. In spite of the presence of MNP clusters, no morphological alterations were observed, supporting the biocompatibility of the ML‒2. MR signal was detected only in the liver and spleen tissues and showed that the MNP′s concentration was not altered from 48 hours to 28 days after ML injection. Using MR data, important pharmacokinetic parameters, such as the effective clearance (half‒life) and peak concentration, were obtained for the liver and spleen.
Development and AFM study of porous scaffolds for wound healing applications
Authors: Doneva T. A. , Yin H. B. , Stephens P. , Bowen W. R. , Thomas D. W.
Published: March 2012

An engineering approach to the development of biomaterials for promotion of wound healing emphasises the importance of a well‒controlled architecture and concentrates on optimisation of morphology and surface chemistry to stimulate guidance of the cells within the wound environment. A series of three‒dimensional porous scaffolds with 80–90% bulk porosity and fully interconnected macropores were prepared from two biodegradable materials – cellulose acetate (CA) and poly (lactic‒co‒glycolic acid) (PLGA) through the phase inversion mechanism of formation. Surface morphology of obtained scaffolds was determined using atomic force microscopy (AFM) in conjunction with optical microscopy. Scanning Electron Microscopy (SEM) was applied to characterise scaffolds bulk morphology. Biocompatibility and biofunctionality of the prepared materials were assessed through a systematic study of cell/material interactions using atomic force microscopy (AFM) methodologies together with in vitro cellular assays. Preliminary data with human fibroblasts demonstrated a positive influence of both scaffolds on cellular attachment and growth. The adhesion of cells on both biomaterials were quantified by AFM force measurements in conjunction with a cell probe technique since, for the first time, a fibroblast probe has been successfully developed and optimal conditions of immobilisation of the cells on the AFM cantilever have been experimentally determined.
Sequence analysis of earthworm hemolysins
Authors: König Simone , Wagner Frank , Kauschke Ellen , Eue Ines
Published: March 2012

Annelids are capable of defending themselves from pathogens and of recognizing degenerated self tissue. These reactions require specialized immune mechanisms that are effected by proteins and cellular reactions. Hemolytic proteins are the most striking humoral defense molecules in the earthworm Eisenia fetida. Beside their hemolytic activity these proteins possess agglutinating, antibacterial, cytotoxic, and clotting properties. Hemolytic proteins both from coelomocytes (CL39,41) and coelomic fluid (H1−3) of wildtype E. fetida were isolated and assigned to fetidin and lysenin using mass spectrometry and bioinformatic tools. Glycosylation was found for H1. In silico analyses of the hemolysins revealed two hemolysin isoforms and consensus sites for N‐glycosylation and peroxidases proximal heme‐binding ligand.
Differences between infrared spectra of normal and neoplastic human gastric cells
Authors: Fujioka Naoko , Morimoto Yuji , Arai Tsunenori , Takeuchi Kyoko , Yoshioka Masahiko , Kikuchi Makoto
Published: March 2012

We investigated the differences in Fourier transform‒infrared (FT‒IR) spectra between normal and neoplastic human gastric cells. The infrared spectra derived from the cancer cells (AGS, SNU‒1, and NCI‒N87) showed a significant increase in infrared absorption in the band around 1240 cm¯1, 1120 cm¯1 and 1080 cm¯1, compared with those from the normal gastric epithelial cells we established in culture. In addition, frequency shifts of 4.6 cm¯1 and 3.8 cm¯1 were seen at the peak absorbance in the bands around 1240 cm¯1 and 1080 cm¯1, respectively. These spectral differences reflected the differences between the phosphate backbone in the normal and neoplastic human gastric cells. The present results suggest that FT‒IR spectroscopy is a potential new tool for gastric cancer diagnosis.
1H MRS phantom studies of BNCT 10B‒carrier, BPA–F using STEAM and PRESS MRS sequences: Detection limit and quantification
Authors: Timonen M. , Kangasmäki A. , Savolainen S. , Heikkinen S.
Published: March 2012

The quantification of boron neutron capture therapy (BNCT) 10B‒carrier, L‒p‒boronophenylalanine‒fructose complex (BPA–F) was studied with phantoms using 1H magnetic resonance spectroscopy sequences PRESS and STEAM at 1.5 and 3.0 T. The results show that typical attainable short echo times of clinical MRS sequences combined with long repetition time result in clinically acceptable quantification accuracy. However, the concentration ratios, which are essential for the treatment planning, can still be reliably measured by using small repetition times. Detection limits of BPA in aqueous phantoms at 1.5 and 3.0 T were evaluated using clinically acceptable measurement time of ~10 min, two typical voxel sizes (153 and 203 mm3) and PRESS and STEAM sequences. The detection limits of BPA in phantom conditions were 0.7 (3.0 T) and 1.4 mM (1.5 T) for PRESS sequence with 203 mm3 voxel.
The silicomolybdic acid spectrophotometric method and its application to silicate/biopolymer interaction studies
Authors: Coradin Thibaud , Eglin David , Livage Jacques
Published: March 2012

The possibility to understand natural strategies to build‒up silica SiO2 networks relies on the investigations of the kinetics of silica precursors polymerization in the presence of biopolymers. The silicomolybdic acid spectrophotometric method allows to study this process at the molecular level, provided that reliable procedures are available. Moreover, special care must be taken to avoid interfering processes induced by the inorganic and/or bio‐organic species found in solution. In order to illustrate the possibilities and limitations of this method, different sets of data are presented and discussed in the context of silica formation control by natural systems.
Single molecule Raman detection of enkephalin on silver colloidal particles
Authors: Kneipp Katrin , Kneipp Harald , Abdali Salim , Berg Rolf W. , Bohr Henrik
Published: March 2012

Enkephalin, an endogeneous substance in the human brain showing morphine‒like biological functions, has been detected at the single molecule level based on the surface‒enhanced Raman signal of the ring breathing mode of phenylalanine, which is one building block of the molecule. For enhancing the Raman signal the enkephalin molecules have been attached to silver colloidal cluster structures. The experiments demonstrate that the SERS signal of the strongly enhanced ring breathing vibration of phenylalanine at 1000 cm−1 can be used as “intrinsic marker” for detecting a single enkephalin molecule without using a specific label molecule. The reported result suggests the use of the phenylalanine 1000 cm−1 SERS line as spectroscopic signature for monitoring single proteins containing this amino acid as a building block.
Structure proposal for a new pyoverdin from a Thai Pseudomonas putida strain1
Authors: Ruangviriyachai Chalerm , Uría Fernández Diana , Schäfer Mathias , Budzikiewicz Herbert
Published: March 2012

From a Thai Pseudomonas putida strain a pyoverdin was isolated whose primary structure was deduced from its mass spectrometric fragmentation pattern. It belongs to the smallest representatives of this group of siderophores comprising only six amino acids.
Feasibility of rapid quantitation of stratum corneum lipid content by Fourier transform infrared spectrometry
Authors: Tsai Jui-Chen , Lo Yu-Li , Lin Ching-Yu , Sheu Hamm-Ming , Lin Jui-Che
Published: March 2012

The permeability barrier of skin resides in the stratum corneum, and its properties are mediated by a series of lipid multilayers, enriched in ceramides, cholesterol, and free fatty acids, segregated within the stratum corneum (SC) interstices. SC lipid content is usually determined by gravimetric methods in conjunction with high performance thin layer chromatography, but these methods are time‒consuming and involve hazardous solvents. The objective of the present study was to develop a method of measuring SC lipid content by Fourier transform infrared spectrometry (FTIR) that is fast and requires no solvents. The IR spectra of isolated porcine SC sheets were recorded using a FTIR spectrometer. SC lipid content was determined by gravimetric methods using chloroform–methanol extraction. The peak area of both the CH2 symmetric (2850 cm−1) and asymmetric (2920 cm−1) stretching bands in the IR spectra of progressively solvent‒extracted porcine SC sheets decreased with increasing amount of SC lipids removed. When spectral analysis was performed by curve‒fitting using GRAMS/32 software between 3000 to 2800 cm−1, peak area ratios of CH2 to CH3 asymmetric stretching bands in the IR spectra of 46 isolated porcine SC samples were correlated to SC lipid content (R2=0.90), with the standard error of measurement of 1.91%. The study demonstrated the feasibility of using FTIR technique to rapidly and accurately measure SC lipid content.
Skimmer CID‒ion trap mass spectrometry of phosphotyrosine‒containing peptides
Authors: Zolodz Melissa D. , Wood Karl V.
Published: March 2012

Proteomic analysis is becoming a popular field in science. Analysis of protein modifications is useful in deciphering cellular functions and errors in pathways that can result in disease. There has been increased interest in the phosphotyrosine proteome. Due to the difficulty in finding the location of the tyrosine phosphorylation site in the tyrosine phosphorylated peptide or even to verify that the parent protein is a phosphotyrosyl‒protein, new analytical tools are being developed. The phosphotyrosine immonium ion can be produced via skimmer CID for detection via ion trap mass spectrometry and is a useful marker for the indication of the presence of a phosphotyrosine residue. Skimmer CID analysis can also be used to differentiate phosphotyrosine‒containing peptides from other phosphorylated peptides. In this study, phosphotyrosine‒containing peptides were analyzed by skimmer CID in an ion trap mass spectrometer. The factors affecting the signal abundance of the phosphotyrosine immonium ion were investigated.
Single molecule force spectroscopy studies of DNA denaturation by T4 gene 32 protein
Authors: Williams Mark C. , Pant Kiran , Rouzina Ioulia , Karpel Richard L.
Published: March 2012

Single molecule force spectroscopy is an emerging technique that can be used to measure the biophysical properties of single macromolecules such as nucleic acids and proteins. In particular, single DNA molecule stretching experiments are used to measure the elastic properties of these molecules and to induce structural transitions. We have demonstrated that double‒stranded DNA molecules undergo a force‒induced melting transition at high forces. Force–extension measurements of single DNA molecules using optical tweezers allow us to measure the stability of DNA under a variety of solution conditions and in the presence of DNA binding proteins. Here we review the evidence of DNA melting in these experiments and discuss the example of DNA force‒induced melting in the presence of the single‒stranded DNA binding protein T4 gene 32. We show that this force spectroscopy technique is a useful probe of DNA–protein interactions, which allows us to obtain binding rates and binding free energies for these interactions.