Detection of carbonate, phosphate minerals and cyanobacteria in rock from the Tomtor deposit, Russia, by Raman spectroscopy.

Samples of rock from the Tomtor Nb - REE (rare-earth elements) deposit (Russia) have been investigated by Raman micro-spectroscopy using visible 532 nm wavelength excitation. Raman spectra of different samples of this rock confirm their composition as calcites and other carbonates such as rhodochrosite, and mixed solid solution phases (Ca, Mn, Fe, Mg, Ba, Sr, REE)(CO3). An association between cyanobacteria and the apatite crystals has been noted Cyanobacteria exhibited Raman modes at 1520-1517 cm-1 located in the double bonds of the central part of the polyene chain of carotenoids. A slight shift of this mode in the apatite-containing samples are dependent upon the compositions of carotenoids, the ratio of the rare earth elements adsorbed by cyanobacteria as well as their interaction with the environment. Laser-induced photoluminescence of REE and Mn+2, obtained as an analytical artifact in the Raman spectra, has been observed in most cases with significant spectral intensity. The luminescence emission of Mn 2+, Sm3+, Eu 3+, Pr3+, Ho3+, Er 3+ in the spectra of the apatite-containing samples obtained with 532 nm excitation can be attributed both to apatite and to other mineral phases with a low concentration which contain these elemental ions. The results obtained in this study allowed us to confirm that the biogenic presence of the cyanobacterial mat had a significant impact on the formation of the unique Nb-REE Tomtor deposit.

[The DC-potential of the brain in older women with postural instability].

The article presents the results of studies of the DC-potential of the brain level distribution in elderly women with postural instability. Analysis of the DC-potential of the brain level distribution was held by mapping obtained by measuring the monopolar values of the DC-potential of the brain and calculating deviations in each of the leads from the average records which were registered in all areas of the head. It is established that elderly women with postural instability DC-potential of the brain level distribution are characterized by increasing in background values and rigid structure of the interaction between brain regions. The disturbance of the principle of the dome-shaped DC-potential of the brain level distribution due to the alignment of values for brain regions was revealed. Factor model with postural instability reflects the control strengthening over the potential falls from the frontal areas of the brain.

Simulating NIRS and MRS measurements during cerebral hypoxia-ischaemia in piglets using a computational model.

We present a group analysis of the changes in cerebral haemodynamics, and the oxidation state of cytochrome-c-oxidase measured using broadband near-infrared spectroscopy (NIRS) and intracellular pH measured by phosphorous ((31)P) magnetic resonance spectroscopy (MRS) during and after cerebral hypoxia-ischaemia (HI) in 15 piglets. We use a previously published computational model of cerebral metabolism in the piglet [1] to integrate these measurements and simulate HI. We successfully simulate changes in cellular metabolism including shifts in intracellular pH observed in the piglet brain during HI. In this process, we optimise physiological parameters in the model identified through sensitivity analysis (such as the rate of glucose metabolism and intracellular lactate concentration), to fit simulated and measured data. The model fits the data reasonably and suggests a 20 % drop in glucose consumption, a ~65 % increase in lactate concentration and ~35 % drop in the cerebral metabolic rate of oxygen (CMRO2) during HI.

The salivary transcriptome of Anopheles gambiae (Diptera: Culicidae) larvae: A microarray-based analysis.

In spite of the many recent developments in the field of vector sialomics, the salivary glands of larval mosquitoes have been largely unexplored. We used whole-transcriptome microarray analysis to create a gene-expression profile of the salivary gland tissue of fourth-instar Anopheles gambiae larvae, and compare it to the gene-expression profile of a matching group of whole larvae. We identified a total of 221 probes with expression values that were (a) significantly enriched in the salivary glands, and (b) sufficiently annotated as to allow the prediction of the presence/absence of signal peptides in their corresponding gene products. Based on available annotation of the protein sequences associated with these probes, we propose that the main roles of larval salivary secretions include: (a) immune response, (b) mouthpart lubrication, (c) nutrient metabolism, and (d) xenobiotic detoxification. Other highlights of the study include the cloning of a transcript encoding a previously unknown salivary defensin (AgDef5), the confirmation of mucus secretion by the larval salivary glands, and the first report of salivary lipocalins in the Culicidae.

Micro-Raman spectra of ugrandite garnet.

The natural garnets from chromite ores associated with pegmatoid pyroxenites of Sangalyk area (Uchaly ore district, southern Urals, Russia) were studied by means of micro-Raman spectroscopy. The compositions of these garnets were close to ugrandite, an isomorphous intermediate group of uvarovite-grossularite-andradite, X(3)Y(2)(SiO(4))(3), X = Ca(2+), Y = Al(3+), Fe(3+), Cr(3+), according to Raman spectra and X-ray microprobe analyses. An assignment of most of the observed bands in visible and near infrared Raman spectra is reported.

Raman spectra of organic compounds kladnoite (C6H4(CO)2NH) and hoelite (C14H8O2)--rare sublimation products crystallising on self-ignited coal heaps.

As minerals, aromatic compounds occur very rarely in nature. Not more than 10 of such minerals are known and most of them were described in the coal deposits where they were formed as a result of coal bed fires or burning of coal waste heaps. Raman spectra of kladnoite C(6)H(4)(CO)(2)NH (natural phthalimide) and hoelite C(14)H(8)O(2), (natural 9,10-anthraquinone) display complex features. Raman microspectroscopy help to detect these phases non-destructively directly in the frame of rare samples. Investigated minerals are transformation products formed from gaseous phase originating in natural pyrolytical process occurring in the frame of coal heaps and coal series outcrops. It is recommended to include Raman spectroscopic characteristics of similar materials in databases for exobiological studies.

Retinal degeneration following failed photoreceptor maturation in 5A11/basigin null mice.

5A11/Basigin is a member of the immunoglobulin gene superfamily which plays an important role in cell-cell interactions in the developing neural retina. These studies were initiated to investigate the distribution of 5A11/Basigin within the mouse retina, as well as the cytoarchitectural and biochemical effects on the retina after the inactivation of the 5A11/Basigin gene in a mouse strain. Immunocytochemical analyses indicated that mouse 5A11/Basigin is located on the surface of Müller cells, the apical and basal surfaces of the retinal pigmented epithelium, and blood vessels. Lower expression levels were found on photoreceptor cell bodies and a portion of the inner segments. Inactivation of the 5A11/Basigin gene in mice resulted in the failure of photoreceptor cells to fully mature. This failed development eventually lead to the degeneration, death and removal of most of the photoreceptors several months after birth. Biochemical analyses indicated that expression of Müller cell specific proteins, including glutamine synthetase and carbonic anhydrase-II, was not effected; however, opsin protein expression never achieved normal adult levels in the 5A11/Basigin null mice. Also, 5A11/Basigin null retinas were considered 'reactive' based on elevated glial fibrillary acidic protein expression. The results presented here suggest that 5A11/Basigin expression on Müller cells and/or the retinal pigmented epithelium is necessary for photoreceptor outer segment biochemical development and structural maintenance. However, the exact role that 5A11/Basigin plays during retinal development remains to be determined.

Cloning, expression and processing of the CP2 neuropeptide precursor of Aplysia.

The cDNA sequence encoding the CP2 neuropeptide precursor is identified and encodes a single copy of the neuropeptide that is flanked by appropriate processing sites. The distribution of the CP2 precursor mRNA is described and matches the CP2-like immunoreactivity described previously. Single cell RT-PCR independently confirms the presence of CP2 precursor mRNA in selected neurons. MALDI-TOF MS is used to identify additional peptides derived from the CP2 precursor in neuronal somata and nerves, suggesting that the CP2 precursor may give rise to additional bioactive neuropeptides.

Egg-laying hormone peptides in the aplysiidae family.

The neuropeptidergic bag cells of the marine mollusc Aplysia californica are involved in the egg-laying behavior of the animal. These neurosecretory cells synthesize an egg-laying hormone (ELH) precursor protein, yielding multiple bioactive peptides, including ELH, several bag cell peptides (BCP) and acidic peptide (AP). While immunohistochemical studies have involved a number of species, homologous peptides have been biochemically characterized in relatively few Aplysiidae species. In this study, a combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS) and electrospray ionization Fourier transform ion cyclotron resonance MS is used to characterize and compare the ELH peptides from related opisthobranch molluscs including Aplysia vaccaria and Phyllaplysia taylori. The peptide profiles of bag cells from these two Aplysiidae species are similar to that of A. californica bag cells. In an effort to characterize further several of these peptides, peptides from multiple groups of cells of each species were extracted, and microbore liquid chromatography was used to separate and isolate them. Several MS-based sequencing approaches are applied to obtain the primary structures of bag cell peptides and ELH. Our studies reveal that (&agr;)-BCPs are 100 % conserved across all species studied. In addition, the complete sequences of (&egr;)-BCP and ELH of A. vaccaria were determined. They show a high degree of homology to their counterparts in A. californica, with only a few amino acid residue substitutions.

Characterization of the Aplysia californica cerebral ganglion F cluster.

The cerebral ganglia neurons of Aplysia californica are involved in the development and modulation of many behaviors. The medially located F cluster has been characterized using morphological, electrophysiological and biochemical techniques and contains at least three previously uncharacterized neuronal population. As the three subtypes are located in three distinct layers, they are designated as top, middle, and bottom layer F-cluster neurons (CFT, CFM, and CFB). The CFT cells are large (92 +/- 25 microm), white, nonuniformly shaped, and located partially in the sheath surrounding the ganglion. These neurons exhibit weak electrical coupling, the presence of synchronized spontaneous changes in membrane potential, and a generalized inhibitory input upon electrical stimulation of the anterior tentacular (AT) nerve. Similar to the CFT neurons, the CFM neurons (46 +/- 12 microm) are mainly silent but do not show electrical coupling or synchronized changes in membrane potential. Unlike the CFT neurons, the CFM neurons exhibit weak action potential broadening during constant current injection. Comparison of the peptide profiles of CFT, CFM, and CFB (10-30 microm) neurons using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry demonstrates distinct peptide molecular weights for each neuronal subtype with the masses of these peptides not matching any previously characterized peptides from A. californica. The mass spectra obtained from the AT nerve are similar to the CFT neuron mass spectra, while upper labial nerve contains many peptides observed in the CFM neurons located in nongranular neuron region.

Characterization of peptides from Aplysia using microbore liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry guided purification.

Liquid chromatography (LC) has been used extensively for the separation and isolation of peptides due to its high selectivity and peak capacity. An approach combining microbore LC with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-MS) detection is described to identify peptides in cells and guide the purification of peptides from the marine mollusc Aplysia californica. Direct MALDI-MS of neurons and processes provides molecular mass information for unknown peptides with almost no sample preparation, and LC-MALDI-MS allows the isolation and purification of these peptides from pooled samples, thus enabling new putative neuropeptides to be isolated from complex cellular samples. Both direct MALDI-MS and LC-MALDI-MS are compared in terms of detecting peptides from neuronal samples. Using both approaches, two peaks from Aplysia californica connectives having molecular masses of 5013 and 5021 have been isolated, partially sequenced and identified as novel collagen-like peptides.

Formation of N-pyroglutamyl peptides from N-Glu and N-Gln precursors in Aplysia neurons.

Matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry is used to examine the formation of N-pyroglutamate (pGlu) in single, identified neurons from Aplysia. Six pGlu peptides are identified in the R3-14 and the R15 neurons that result from in vivo processing of peptides containing either Glu or Gln at their respective N-termini. Moreover, we show that Glu-derived pGlu is not a sample collection or measurement artifact. The pGlu peptides are detected in isolated cell bodies, regenerated neurites in culture, interganglionic connective nerves, cell homogenates, and collected releasates. We also demonstrate that R3-14 cells readily convert a synthetic N-Glu peptide to its pGlu analogue, indicating the presence of novel enzymatic activity.

Monitoring cellular release with dynamic channel electrophoresis.

A channel electrophoresis system consisting of a 50 microns by 75 mm by 25 mm separation channel has been adapted to follow stimulated release from individual and small groups of isolated neurons. The cells of interest are placed in a nanoperfusion chamber located near the exit of a sampling capillary. The capillary is scanned across the mouth of the channel so that compounds released from the cells are dynamically introduced into the separation channel. The position of the sampling capillary along the channel entrance yields temporal information, and electrophoresis in the channel length dimension provides the chemical data. NDA/CN- is placed in the inlet vial between the sampling capillary and channel so that primary amine-containing compounds released from the cell are derivatized prior to separation as they enter the channel. The performance of this method is evaluated, and the optimum NDA/CN- concentration and separation conditions for this on-line derivatization are presented, with detection limits for most underivatized amino acids of approximately 500 nM at a particular time slice. The time-resolved electropherograms from single and a small group of cerebral ganglion neurons from Aplysia californica stimulated with KCl show multiple components released with different time courses.

Mass spectrometric survey of interganglionically transported peptides in Aplysia.

The major ganglionic connectives in Aplysia are assayed to determine putative neuropeptides. Matrix-assisted laser desorption/ionization mass spectrometry allows direct measurement of peptides in a nerve. Many previously characterized peptides are observed, including APGWamide, buccalins, small cardioactive peptides, and egg-laying hormone. Several unreported peptides are detected in specific nerves, suggesting they may have important physiological roles. Furthermore, novel processing products of the L5-67 precursor peptide and the APGWamide/cerebral peptide 1 prohormone are strongly suggested, and their interganglionic transport demonstrated.

Proteolytic processing of the Aplysia egg-laying hormone prohormone.

By using matrix-assisted laser desorption/ionization time-of-flight MS, individual peptidergic neurons from Aplysia are assayed. A semiquantitative method is developed for comparing single-cell profiles by using spectral normalization, and peptides are localized to specific cells by mass spectrometric cell mapping. In addition to all previously identified products of the egg-laying hormone (ELH) gene, other peptides are formed from proteolytic hydrolysis of Leu-Leu residues within ELH and acidic peptide (AP). AP exhibits further processing to yield AP1-20 and AP9-27. These peptides appear to be colocalized in vesicles with ELH, transported to specific neuronal targets, and released in a Ca2+-dependent manner. A differential peptide distribution is observed at a specific target cell, and a low-frequency variation of AP, [Thr21]AP, is detected in a single animal.

Excess salt removal with matrix rinsing: direct peptide profiling of neurons from marine invertebrates using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF-MS) is a viable technique for the examination of biological environments. Clearly, sample preparation plays a pivotal role in the ability to obtain mass spectra from samples as complex as biological cells. The physiological salt concentrations associated with neurons from marine specimens interfere with MALDI analysis. A unique and simple rinsing procedure allows cellular clusters, individual neurons and connective tissues to be directly assayed for peptides with minimal sample handling. Isolated cells and tissues, including egg-laying hormone-releasing cells, from the central nervous systems of the model marine molluscs Aplysia californica and Pleurobranchaea californica are used to demonstrate the salt removal method. In addition to facilitating sample ionization, the MALDI matrix 2,5-dihydroxybenzoic acid serves to (i) aid in microdissections by stabilizing cell membranes, (ii) deactivate endogenous proteolytic enzymes and (iii) reduce high salt concentrations in order to improve spectral quality. Representative MALDI mass spectra are presented which indicate the presence of several neuroactive peptides previously characterized by conventional biochemical methods. More than ten individual peptides can be detected in a single cell. In spite of the chemically complex sample, the mass spectra are surprisingly free of extraneous peaks. Furthermore, both mass resolution and mass accuracy are similar to those encountered with more common MALDI samples and protocols.

[The use of food fibers in the treatment of biliary system lesions in children]. / Primenenie pishchevykh volokon v lechenii porazhenii biliarnoi sistemy u detei.

Lipid peroxidation was studied in children with biliary tract diseases. The data on the activation of lipid peroxidation have permitted the authors to use and recommend wheat bran as an antioxidant in the treatment of children with biliary tract diseases.

[Membrane-destructive processes in lesions of the biliary system in children]. / Membranodestruktivnye protsessy pri porazhenii biliarnoi sistemy u detei.

The authors analyze the data on lipid peroxidation in children with biliary system derangement. Lipid peroxidation was found to be significantly activated in children with exacerbation of chronic cholecystocholangitis and hypokinetic dyskinesia of the biliary tract. The data obtained suggest the development of the cytolysis syndrome in patients with inflammatory and functional diseases of the biliary tract. It is therefore recommended that the complex of treatment measures may include membrano-stabilizing agents.

Source of the slippage in the universal joints of the Hoffmann external fixator.

An investigation was conducted to determine what improvements in the resistance to slippage could be obtained in selected interfaces (rod/clip torsional, cheek/bowl and cheek/clip) of the Hoffmann external fixator. The modification involved changing the standard wing-nut clamp for a bolt with a thread of 7 mm and a 1 mm pitch and placing an FAG 28-303 thrust-bearing (needle roller and cage assembly) between the bolt and the cheek. The results showed a significant improvement in the slippage values of all interfaces; increases of approximately six times were obtained at all torque values of the wing-nut clamp or fastener tested. Such improvements would markedly increase the reliability of external fixation systems and thus reduce the incidence of loss-of-reduction of fracture due to slippage of the universal joint.

Stiffness of bone underlying the tibial plateaus of osteoarthritic and normal knees.

The mechanical properties of normal cancellous bone in the proximal tibia have been reported extensively in previous studies in terms of support of a total knee arthroplasty (TKA); yet, little is known about these mechanical properties in the osteoarthritic (OA) state. Fifteen normal and 28 OA tibial plateaus, obtained from autopsy or TKA, were mechanically tested using an indentor technique to assess the variation of stiffness patterns. The medial:lateral stiffness ratio calculated for the normal plateaus was significantly different from the ratios computed for specimens with medial compartment OA and lateral compartment OA; however, the ratio was unchanged in tricompartment OA. These data should receive greater consideration in the design of TKA, which has traditionally been designed on the mechanical properties of normal tibiae.