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PubMed1995

Low frequency analysis of opening sound for detection of single leg separation of Björk-Shiley Convexo-Concave heart valves.

The aim of the study was to evaluate the potential of low frequency analysis of valve opening sounds in order to detect the presence of single leg separation of the outlet strut of Björk-Shiley convexo-concave (BSCC) valves. Single leg separation is believed to precede outlet strut fracture. Phonocardiograms (PCG) of 28 patients with BSCC mitral valves were recorded and filtered to limit the frequency bandwidth between 90 and 1400 Hz (-20 dB). Twenty-four patients had BSCC valves that were presumably unimpaired and four patients had BSCC valves with single leg separation. Spectral analysis consisted of computing the power spectrum for 30 opening sounds for each patient using a fast Fourier transform (FFT) algorithm on an IBM-PC compatible computer. For each patient, the power spectra of the selected opening sounds were averaged and normalized in amplitude on a 0-100% linear scale. A ratio of the high to the low frequency area of the averaged power spectra was computed and evaluated as a diagnostic feature to identify the valves with single leg separation. Six cut-off frequencies serving to distinguish between high and low frequency areas of the spectra were tested: 400, 450, 500, 550, 600, and 650 Hz. The results showed that the high-to-low frequency area ratios tested were all able to identify valves with single leg separation. The correct classification performance was 96.4%. The sensitivity to detect valves with single leg separation was 75% and the specificity was 100%. The positive predictive value was 100% and the negative predictive value 96%. The study confirmed the potential of low frequency analysis of valve opening sounds to detect single leg separation of the outlet strut of BSCC valves implanted in humans.

Algorithms↗
PubMedDate not supplied

The direct separation of the diastereoisomers and enantiomers of the fungicide triadimenol by micellar electrokinetic capillary chromatography.

The direct chiral separation of the four enantiomers of the systemic fungicide triadimenol has been investigated using micellar electrokinetic capillary chromatography (MECC) with cyclodextrin (CD) chiral selectors and organic modifiers. The capillary operating temperature, applied voltage, and column diameter were all shown to be important factors in achieving an enantioselective separation. The addition of various CDs to the micellar buffer mixture was evaluated. The type of CD and its concentration affected the degree of separation, with the best separation of the enantiomers demonstrated for heptakis 2,6-di-O-methyl-beta-cyclodextrin (di-OMe-beta-CD). The addition of organic modifiers and CDs to the background electrolyte further enhanced separation. The best separation of the four enantiomers was obtained using an MECC buffer system consisting of 20% methanol, 0.02 M hydroxypropyl-beta-cyclodextrin (HO-Pr-beta-CD), and 0.05 M sodium dodecyl sulfate (SDS) in 0.02 M sodium borate and 0.02 M disodium hydrogen phosphate. The reported method demonstrates how the separation of enantiomers can be achieved by systematically varying the parameters in an MECC buffer system.

Capillary Action↗
PubMedDate not supplied

High-performance capillary electrophoretic separation of carbohydrates with indirect UV detection using diethylamine and borate as electrolyte additives.

The separation of underivatized carbohydrates was investigated using capillary zone electrophoresis with indirect UV detection based on sorbic acid or riboflavin. In comparison with sodium hydroxide, the separation of carbohydrates was greatly improved using diethylamine (DEA) as an electrolyte additive. Since the conductivity of DEA is much lower than that of sodium hydroxide, a stable baseline and a 3-5 times improvement in separation efficiency was observed at a pH as high as 12.6. It was found that DEA reduced the electrophoretic mobility of carbohydrates by formation of ion-pairs, and also reduced the electroosmotic flow by masking the silanol groups at the capillary surface. Many monosaccharides, including glucose, rhamnose, mannose, and fructose, which have very similar pKa values, were completely separated using 5% DEA at pH 12.6. The separation of di- and trisaccharides using indirect detection with a borate buffer at pH 9.5 was also investigated. The separation of disaccharides was greatly improved with borate complexation using riboflavin as a background electrolyte (BGE) over the sodium hydroxide and DEA electrolyte system with sorbic acid as BGE. The resolution of carbohydrates increased as pH increased, and sucrose, trehalose, raffinose, and maltotriose were successfully separated at pH 11.8.

Boric Acids↗
PubMed2005

Cell separation between mesenchymal progenitor cells through porous polymeric membranes.

This study investigates the separation of two types of marrow stromal cells, KUSA-A1 osteoblasts and H-1/A preadipocytes, by filtration through various porous polymeric membranes. It was found that KUSA-A1 permeates better than H-1/A cells through 12-microm polyurethane foaming membranes. This appears to be due to the relatively smaller cell size of KUSA-A1 cells. In addition, when feed solutions containing suspensions of either cell type or a mixture of the two were used, the permeation ratio was relatively low (< 6%) through polyurethane and surface-modified polyurethane foaming membranes. It was also found that there was some degree of separation between KUSA-A1 and H-1/A cells (separation factor = 1.8) with nylon-net filter membranes, but no separation was obtained when filters made of nonwoven fabrics or silk screens were used. This ability of the nylon-net filter membranes to separate the two cell types was due to a sieving effect that results from an optimal pore size. Finally, permeation of a solution of human serum albumin through the membrane following filtration of the cells did not result in a separation of cells in the recovery solution.

Adipocytes↗
PubMed2000

Methodological study of cell separation with domestic immunomagnetic beads.

To establish the method of cell separation with domestic immuomagnetic beads, three methods were investigated. Direct method, SPA method and Biotin-Avidin method were applied to separate cell strain Hut-78 and CD4 positive cells. Separation rate of strain Hut-78 was more than 90% in direct method. Detachment rate with papain was over 95%. Cell activity was well retained. SPA method and Biotin-Avidin methods were also effective, but the direct method was superior to the other two techniques. Before separated by the direct method, CD4 positive cells constituted 46.4% +/- 6.4% of mononuclear cells (MNC), but in eliminated suspension there was only 6.2% +/- 2.3% CD4 positive cells left. In the separated part, 80.6% +/- 7.2% of the cells combined with the beads. It is concluded that the direct method in separating cells had high sensitivity and specificity.

CD4-Positive T-Lymphocytes↗
PubMed1988

Opiate modulation of separation-induced distress in non-human primates.

Infant rhesus monkeys respond to separation from their mothers with a dramatic increase in vocalizations and activation of autonomic and pituitary-adrenal systems. Using the mother-infant separation paradigm in rhesus monkeys, we focused on the role of opiate systems in modulating the behavioral and neuroendocrine consequences of a brief, naturally occurring stressor. In the first experiment, morphine 0.1 mg/kg significantly decreased separation-induced vocalizations without affecting activity levels. In the second experiment, naloxone 1.0 mg/kg increased distress vocalizations but lower doses had no effect. In the third experiment we blocked the effect of morphine 0.1 mg/kg with naloxone 0.1 mg/kg, a dose of naloxone that had no intrinsic effects of its own. This suggests that the reduction of separation-induced vocalizations by morphine is mediated by opiate receptors. The last experiment demonstrated that separation-induced increases in pituitary-adrenal hormones can also be modulated by opiate agonists and antagonists. These findings are consistent with work in non-primate species and support the hypothesis that opiate receptors are specifically involved in mediating separation-induced vocalizations and pituitary-adrenal activation in primates.

Animals↗
PubMed1977

Characterization of functionally distinct lymphoid and myeloid cells from human blood and bone marrow. II. Separation by velocity sedimentation.

Velocity sedimentation in a zonal rotor using gradients of uniform osmolarity was used to separate leukocyte subpopulations from human blood and bone marrow. The separations were performed at high sedimentation rates having the advantage of rapidity over conventional unit gravity separations. Myeloid stem cells (CFU-C) and cells reactive with phytohemagglutinin (PHA), Concanavalin A (Con A), and in mixed leukocyte culture (MLC) were separated and their sedimentation profiles obtained. CFU-C sedimented ahead of lymphoid cells and behind mature myeloid elements. Two distinct marrow subpopulations separated by velocity sedimentation were consistently stimulated by Con A, and variably stimulated by PHA and MLC reactions. Both large cells (predominantly myeloid) and small cells (predominantly lymphoid) from bone marrow were stimulated by Con A in [3H]thymidine incorporation assays. When separated subpopulations showing stimulation by Con A were mixed, inhibition of [3H]thymidine incorporation resulted.

Blood Cells↗
PubMed1982

Antigen-specific electrophoretic cell separation (ASECS): isolation by human T and B lymphocyte subpopulations by free-flow electrophoresis after reaction with antibodies.

The electrophoretic mobility of human lymphocytes can be reduced by incubation with surface antigen specific antibodies under non-capping conditions. This renders subpopulations of human peripheral blood lymphocytes accessible to separation by free-flow electrophoresis. After reaction of lymphocyte preparations with anti-IgM antibody and a fluorescent second antibody, B lymphocytes showed a considerable shift in position in preparative cell electrophoresis and could be separated with high yield, purity and vitality. Similarly, a T cell subpopulation reactive with the monoclonal antibody T811 could be isolated, even though only small amounts of this antibody were bound, by using a double-sandwich method. Non-specific antibody uptake via Fc-receptors did not contribute to the observed shift of antibody-labelled cells to lower electrophoretic mobility. Flow cytometric analysis showed that cells were separated according to their antigen density. Thus cell electrophoresis can be used to separate antibody-labelled cells. With a flow rate of 100,000 cells/sec this method has a much higher separation capacity than fluorescence-activated cell sorting. The described method should be applicable to the separation of a wide range of cell populations for which specific antibodies are available.

Animals↗
PubMed1996

Repeated maternal separation of preweanling rats attenuates behavioral responses to primary and conditioned incentives in adulthood.

Early social experience has profound effects on a wide spectrum of behaviors and neurochemical correlates in the rat. Repeated separation of rat pups from their dam during the early neonatal period causes acute perturbation of neuroendocrine and physiological status. The chronic sequelae of repeated separations have not been studied as extensively as the acute responses. Altered social experience at a later developmental stage, postweaning isolation rearing, is known to induce enduring changes in the behavioral responses to reward and reward-related stimuli in maturity. We have evaluated the influence of repeated early maternal separation on the responses to both primary and conditioned incentives in mature rats. Separated animals showed enhanced weight gain, a blunted locomotor response to a novel environment and a blunting of the response to both negative and positive contrast effects. Female separated animals, but not males, exhibited a profound attenuation of the acquisition of a conditioned anticipatory locomotor response to the presentation of food. These data are discussed with respect to the putative involvement of ventral striatal dopamine systems in reward mechanisms and the potential utility of early maternal separation as an animal model of depression.

Animals↗
PubMed1982

Evaluation of density gradient separation methods.

A new method for evaluating the effectiveness of isopycnic separation processes is developed and explored. This technique is designed to measure the ability of a separation technique to attain the goals of a sorting process. The performance of a separation process is expressed in terms of an inconsistency number, I, whose value ranges from zero to unity. Processes which function perfectly are characterized by an I value of zero. Separation processes which merely subdivide a sample are characterized by an I value of unity. The validity of using I to measure the performance of separation processes was established by demonstrating that alterations in the performance of a well characterized separation technique were fully reflected by changes in the I value for the process. The capacity of four different techniques for ordering red cells with respect to their density was then shown to lie in a definite hierarchy. This hierarchy can be expressed as: Murphy technique (I = 0.21) greater than albumin density gradient (I = 0.43) greater Stractan density gradient (I = 0.53) greater than Percoll density gradient (I = 0.73). The performance was found to be dependent on the exact operating conditions employed and the specific fraction of red cells isolated.

Cell Separation↗
PubMed2004

Particle separation using ultrasound can radically reduce embolic load to brain after cardiac surgery.

BACKGROUND: Microembolism during cardiopulmonary bypass has been suggested as being the predominant cause of neurocognitive disorders after cardiac surgery. Shed blood, normally retransfused into the patient during cardiopulmonary bypass, is a major source of lipid microemboli in the brain capillaries. A newly developed technique based on acoustic standing-wave separation of particles in fluid in microchannels, with the capacity to remove lipid particles in blood, is presented. METHODS: A separator consisting of eight parallel, high-fidelity microfabricated channels was actuated with an ultrasound field to create a standing wave. Three different concentrations of lipid particles (diameter, 0.3 microm) were added to blood samples with increasing hematocrits and introduced into the separator channels to separate lipid particles and erythrocytes. RESULTS: The mean separation rates for lipid particles were 81.9% +/- 7.6% and for erythrocytes 79.8% +/- 9.9%, and both were related to the hematocrit level of the incoming blood sample. The procedure was atraumatic and did not cause hemolysis. CONCLUSIONS: Particle separation by means of an acoustic standing-wave technique can be used for atraumatic and effective removal of lipid particles from blood, with the possible clinical implication of reducing neurocognitive complications after cardiopulmonary bypass.

Animals↗
PubMed2001

Neural correlates of maternal separation in rhesus monkeys.

BACKGROUND: The neurobiological basis of stress and anxiety in primates remains poorly understood. In this study, we examined the neural response to a naturalistic social stressor: maternal separation. We used rhesus monkeys as an animal model because of their close phylogenetic affinity with humans. METHODS: Six juvenile rhesus monkeys received [(18)F]-fluorodeoxyglucose positron emission tomography scans following 1) a period together with their mothers and again after separation from their mothers 2) with or 3) without visual contact. Image subtraction revealed brain regions that exhibited altered activity during separation. In addition, plasma cortisol concentrations obtained following each condition were tested for correlations with regional brain activity. RESULTS: Maternal separation activated the right dorsolateral prefrontal cortex and the right ventral temporal/occipital lobe. There was also decreased activity in left dorsolateral prefrontal cortex associated with separation stress. Correlational analyses demonstrated these activated and deactivated regions to be positively and negatively correlated with cortisol, respectively. Additionally, correlational analyses revealed cortisol-related activation in brainstem areas previously implicated in stress and anxiety. CONCLUSIONS: In juvenile rhesus monkeys, the stress of maternal separation is associated with activation in the right dorsolateral prefrontal cortex and ventral temporal/occipital lobes and decreased activity in the left dorsolateral prefrontal cortex.

Aggression↗
PubMed1991

Partitioning of cells in dextran-poly(ethylene glycol) aqueous phase systems. A study of settling time, vessel geometry and sedimentation effects on the efficiency of separation.

The effect of prolonged settling times (up to 2 h), in high- and low-phase columns, on the cell partition ratios measured and on the separability of cell populations was examined. With closely related cell populations, modelled by rat erythrocytes in which subpopulations of red blood cells of distinct age were labeled isotopically, it was found that partitioning proceeds over the entire time period examined as evidenced by the continuous change in relative specific activity of cells in the top phase as the partition ratio falls. In control cell sedimentation experiments in top phase there was almost no change in the quantity of cells present when vertical settling (i.e., high-phase columns) was used and no separation of specific subpopulations was found. In the horizontal settling mode the initially higher cell partition ratio, as compared to vertical settling, decreased to a greater extent with longer time intervals; a given purity of cells only being obtained at a lower partition ratio than in the vertical settling mode. Cell sedimentation in top phase was appreciable with time in the horizontal settling mode but did not result in a separation of cell subpopulations. The effect of relative cell partition ratios and sizes in high- and low-phase columns on the efficiency of separation was examined by use of rat or sheep 51Cr-labeled red cells mixed with an excess of human unlabeled erythrocytes. Rat and sheep red cells are appreciably smaller than human erythrocytes. Rat red cells have higher, and sheep red cells lower partition ratios than human erythrocytes. With vertical settling, over a 2-h period, there is no appreciable contribution to the change in relative specific activities by cell sedimentation. However, the more rapid sedimentation of the larger human red cells has, with time, a measurable effect on the relative specific activities obtained during cell partitioning when run in the horizontal mode: enhancing the rat-human and diminishing the sheep-human cell separations. Partitioning cells in high-phase columns is of advantage with respect to increasing separation efficiency and virtually eliminating the influence of other physical parameters (e.g., cell size). Since the cell partitioning process continues for long periods of time, yielding ever-lower partition ratios with increasing proportions of cells with higher P values, a time may be selected which balances desired relative cell purity and yield.

Animals↗
PubMedDate not supplied

Adult separation anxiety: psychometric properties of a new structured clinical interview.

Separation anxiety has traditionally been characterized and assessed as a disorder that is unique to childhood. Yet the core symptoms of separation anxiety, i.e. excessive and often disabling distress when faced with actual or perceived separation from major attachment figures, may persist or even arise during adulthood. We report on the psychometric properties of a new structured clinical interview designed to assess symptoms of separation anxiety as experienced both during childhood and adulthood. This instrument, called the Structured Clinical Interview for Separation Anxiety Symptoms (or SCI-SAS), was administered as part of an assessment battery to 91 adult psychiatric outpatients and 20 non-psychiatric controls. Results indicate that this instrument displays excellent psychometric properties, including good internal consistency, a clear factor structure, and exceptional levels of convergent and discriminate validity. These results highlight the feasibility and potential clinical utility of assessing age-appropriate symptoms of separation anxiety experienced during adulthood.

Adult↗
PubMed1997

Rapid purification of glial cells using immunomagnetic separation.

By purifying glial cells from brain tissue containing a heterogeneous cell population, a number of interactions that define glial cell diversification and function within the central nervous system have been determined. The current methods for purifying glial cells, however, can be time consuming and costly. In the following study we have adapted the technique of immunomagnetic separation to separately enrich 0-2A progenitor cells and astrocytes from the rat central nervous system (CNS). In this procedure, tissue from the CNS was enzymatically dissociated and incubated in a primary antibody specific to a surface antigen found on the target cell type (e.g. A2B5 or RAN-2). The target cells were then immunologically coupled to magnetic beads, which were precoated with a secondary antibody specific to the primary, and then separated out from the heterogeneous cell population using a magnetic field. We found that the immunomagnetic separation procedure, which was completed within 2 h, produced a near pure population of glial cells (> 99%). This was confirmed by the absence of unbound cells in the bead-bound fraction. The identification and viability of bead-bound cells were established by culturing these cells and subsequently examining their morphology and antigenic expression. This study shows that glial cell types can be separated out of brain tissue to near purity using immunomagnetic separation. This simple procedure is reliable, inexpensive, and achieves levels of purity and viability comparable with currently available techniques of immunopanning and fluorescence-activated cell sorting, within a fraction of the time.

Animals↗
PubMed2003

Functional changes and motility characteristics of Japanese Black bull spermatozoa separated by Percoll.

Spermatozoa from two Japanese Black bulls (Bull-ATF and Bull-KTG) were separated by centrifugation at 700 x g for 15min in modified TALP with or without 45-90% Percoll. Control washed spermatozoa and those collected from the bottom of 45 and 90% Percoll fractions were examined for viability and membrane integrity (using Hoechst bis-benzimide 33258 or propidium iodide and 6-carboxyfluorescein diacetate (PI-CFDA)), acrosomal status (using fluorescence isothiocyanate (FITC) conjugated Pisum Sativum agglutinin (PSA) and Peanut agglutinin (PNA), Naphthol Yellow S and Erythrosin B (NE) or triple staining (TS)), capacitation status (using chlortetracycline (CTC)), motility characteristics (using a computer-assisted sperm motion analysis system (CASA)) and for in vitro fertility. Percoll-separated spermatozoa showed greater viability and membrane integrity than controls, as determined by supravital staining. Differences were observed in the results regarding viability and acrosomal status of spermatozoa among sperm staining methods. Bull-ATF, which showed significantly greater in vitro fertility than Bull-KTG (P<0.05), showed a significantly higher rate of CTC-B-pattern (capacitated) spermatozoa (P<0.01) than Bull-KTG. The motility characteristics of control washed spermatozoa and those separated by 45-90% Percoll were analyzed by CASA. More motile and progressively motile spermatozoa were observed in the fraction at the bottom of the 90% Percoll solution than in the 45% Percoll fraction or in controls (P<0.01). Moreover, the spermatozoa of Bull-KTG, which showed lower in vitro fertility than Bull-ATF, did not show significant differences in motility from those of Bull-ATF. These results provided basic information about Japanese Black bull spermatozoa, and suggested that spermatozoa with greater motility and viability can be obtained by Percoll separation than without separation. However, Percoll separation did not enhance their in vitro fertility.

Acrosome↗
PubMed2004

Magnetic cell separation using antibody binding with protein a expressed on bacterial magnetic particles.

Bacterial magnetic particles (BacMPs) are efficient platforms of proteins for surface display systems. In this study, mononuclear cells from peripheral blood were separated using BacMPs expressing protein A on the BacMP membrane surface (protein A-BacMPs), which were complexed with the Fc fragment of anti-mouse IgG antibody. The procedure of positive selection involves incubation of mononuclear cells and mouse monoclonal antibodies against different cell surface antigens (CD8, CD14, CD19, CD20) prior to treatment with protein A-BacMP binding with rabbit anti-mouse IgG secondary antibodies. Flow cytometric analysis showed that approximately 97.5 +/- 1.7% of CD19(+) and CD20(+) cells were involved in the positive fraction after magnetic separation. The ratio of the negative cells in the negative fraction was approximately 97.6 +/-1.4%. This indicates that CD19(+) and CD20(+) cells can be efficiently separated from mononuclear cells. Stem cell marker (CD34) positive cells were also separated using protein A-BacMP binding with antibody. May-Grunwald Giemsa stain showed a high nuclear/cytoplasm ratio, which indicates a typical staining pattern of stem cells. The separated cells had the capability of colony formation as hematopoietic stem cells. Furthermore, the inhibitory effect of magnetic cell separation on CD14(+) cells was evaluated by measurement of cytokine in the culture supernatant by ELISA when the cells were cultured with or without lipopolysaccharide (LPS). The induction of IL1-beta, TNFalpha, and IL6 was observed in the presence of 1 ng/mL LPS in all fractions. On the other hand, in the absence of LPS, BacMPs had little immunopotentiation to CD14(+) cells as well as that of artificial magnetic particles, although TNFalpha and IL6 were slightly induced in the absence of LPS in the positive fraction.

Binding Sites, Antibody↗
PubMed2001

Fluoxetine enhances cell proliferation and prevents apoptosis in dentate gyrus of maternally separated rats.

The mother-infant relationship is an instinctive phenomenon, and loss of maternal care in early life influences neonatal development, behavior and physiologic responses.(1,2) Furthermore, the early loss may affect the vulnerability of the infant to neuropsychiatric disorders, such as childhood anxiety disorders, personality disorders and depression, over its lifespan.(3,4) Fluoxetine is prescribed worldwide for depression and is often used in the treatment of childhood mental problems related to maternal separation or loss of maternal care.(5,6) In the present study, fluoxetine was administrated to rats with maternal separation to determine its effects on neuronal development, in particular with respect to cell proliferation and apoptosis in the dentate gyrus of the hippocampus. Rat pups were separated from their mothers and socially isolated on postnatal day 14 and were treated with fluoxetine (5 mg kg(-1)) and 5-bromo-2'-deoxyuridine (BrdU) (50 mg kg(-1)) for 7 days, after which immunohistochemistry and a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining were carried out. In the pups with maternal separation treated with fluoxetine, the number of BrdU-positive cells was significantly increased and that of TUNEL-positive cells was significantly decreased in the dentate gyrus compared to pups with maternal separation that did not receive fluoxetine treatment. These findings indicate that fluoxetine affects new cell proliferation and apoptosis, and we propose that fluoxetine may be useful in the treatment of maternal separation-related diseases.

Animals↗