Changes In Absolute Concentrations Research Articles

KYNURENINE METABOLITES AND INFLAMMATION MARKERS IN DEPRESSED PATIENTS TREATED WITH FLUOXETINE OR COUNSELLING

1. Depression could result from changes in tryptophan availability caused by activation of the kynurenine pathway as a result of inflammation. In the present study, we examined patients newly diagnosed with depression to determine whether kynurenines and related factors change in parallel with improvements in mood. 2. Concentrations of 5-hydroxytryptamine (5-HT; serotonin), 5-hydroxyindoleacetic acid (5-HIAA), oxidized tryptophan metabolites, brain-derived neurotrophic factor (BDNF) and inflammatory mediators (interleukin (IL)-2, C-reactive protein (CRP), neopterin) were measured in peripheral blood during an 18 week period of treatment with fluoxetine, fluoxetine plus tri-iodothyronine (T(3)) or psychiatric counselling. 3. The results showed significant improvements in mood, with reduced 5-HT concentrations in patients given fluoxetine and a rise in plasma tryptophan in patients given counselling or fluoxetine and T(3). The addition of T(3) to the fluoxetine regimen appeared to slow recovery from depression, although the use of T(3) was associated with a fall in thyroxine concentrations. Changes in 5-HT concentrations did not correlate with psychiatric scores and were seen only in drug-treated groups, not those given counselling. There were no associated changes in absolute concentrations of kynurenines, BDNF, CRP, neopterin or IL-2. With fluoxetine treatment, there were correlations between the concentrations of kynurenine metabolites and the psychiatric rating scores, whereas no correlations were found with BDNF or inflammatory markers. 4. It is concluded that depression scores are largely independent of inflammatory status, but kynurenine metabolism may be related to the degree of depression after fluoxetine treatment.

Estimation of Hg 0 exchange between ecosystems and the atmosphere using 222Rn and Hg 0 concentration changes in the stable nocturnal boundary layer

The goal of this study was to test a 222Rn/Hg 0 method to measure exchange fluxes of Hg 0 between ecosystems and the atmosphere complementing gradient-based micrometeorological methods which are difficult to apply when exchange fluxes are very low, during calm nights, and over heterogeneous surfaces. The method is based on absolute concentration changes of Hg 0 and of the trace gas 222Rn over several hours in the stable nocturnal boundary layer (NBL) when absolute gas concentrations change according to the source or sink strength of the underlying landscape. 222Rn accumulations were observed in 28 of 66 measured nights in an urban area and in 14 of the 40 nights at a subalpine grassland. Concurrent and significant increases in atmospheric Hg 0 concentrations were observed 22 times in the urban area and calculated Hg 0 emissions—for the first time measured over a city area—averaged 6.4±0.9 ng m −2 h −1. Concurrent changes in Hg 0 in the stable NBLs at the subalpine site were very small and significant only nine times with calculated Hg 0 fluxes averaging −0.2±0.3 ng m −2 h −1, indicating that the flux of Hg 0 in the grassland was a very small net deposition of atmospheric Hg 0 to the ecosystem. At the subalpine grassland the 222Rn/Hg 0 method compared reasonably well to a modified Bowen ratio (MBR) method applied during turbulent conditions (−1.9±0.2 ng m −2 h −1 [or −1.7±0.4 ng m −2 h −1 during nights only]). The MBR, however, was not applicable in the urban area due to high surface roughness. We conclude that the 222Rn/Hg 0 method—although limited to nighttime periods in our study—can complement gradient-based methods during stable NBL periods and can be used over heterogeneous surfaces when conventional micrometeorological approaches are not applicable.

Quantitative optical imaging of brain activity—human and animal studies

In order to overcome the problems associated with near-infrared optical imaging (NIR-imaging) such as the lack of the quantification and poor spatial resolution, we developed a 64-channel time-resolved optical imaging system, by which we could obtain quantitative functional images of human brain activity. Reflectance tomographic images of the changes in oxy-hemoglobin [oxy-Hb], deoxy-hemoglobin [deoxy-Hb], and total-hemoglobin [t-Hb] associated with neural activation were obtained, and given as absolute concentration changes. Then, the obtained optical functional images were superimposed on 3-D images of the subject's brain reconstructed from MRI, on which fMRI images were also superimposed. Very interestingly, but curiously, we found that the activation maps of [oxy-Hb] rather than [deoxy-Hb] were very reasonable and similar to those of the fMRI. The maximum increase in [oxy-Hb] due to finger tapping was about 1 μM, whereas in several cognitive tasks such as the digit span task, the increase was much larger, at 3–8 μM. The optical imaging system employed here can be applied to the subjects of all ages and be used at the bedside as well. By simplifying and miniaturizing the imaging system, we could construct a conventional single channel oxygen monitor for clinical use, by which we could quantify the changes of [oxy-, deoxy- and total Hb] during neuronal activation in each subject and, therefore, statistical analysis became possible.

Diurnal changes in gas exchange and carbon partitioning in needles of fast- and slow-growing families of loblolly pine (Pinus taeda).

We investigated diurnal and seasonal changes in carbon acquisition and partitioning of recently assimilated carbon in fast- and slow-growing families of loblolly pine (Pinus taeda L.) to determine whether fast-growing families exhibited greater carbon gain at the leaf level. Since planting on a xeric infertile site in Scotland County, NC, USA in 1993, five Atlantic Coastal Plain (ACP) and five "Lost Pines" Texas (TX) families have been grown with either optimal nutrition or without fertilization (control). In 1998 and 1999, gas exchange parameters were monitored bimonthly in four families and needles were analyzed bimonthly for starch and soluble sugar concentrations. Although diurnal and seasonal effects on net photosynthesis (A(net)) and maximum rate of light-saturated photosynthesis (A(max)) were significant, few family or treatment differences in gas exchange characteristics were observed. The A(net) peaked at different times during the day over the season, and A(max) was generally highest in May. Instantaneous water-use efficiency (WUE(i)), derived from gas exchange parameters, did not differ among families, whereas foliage stable isotope composition (delta(13)C) values suggested that TX families exhibited lower WUE than more mesic ACP families. Although there were no diurnal effects on foliar starch concentrations, needles exhibited pronounced seasonal changes in absolute concentrations of total nonstructural carbohydrates (TNC), starch and soluble sugars, and in partitioning of TNC to starch and sugars, mirroring seasonal changes in photosynthesis and shoot and root growth. In all families, foliar starch concentrations peaked in May and decreased to a minimum in winter, whereas reducing sugar concentrations were highest in winter. Some family and treatment differences in partitioning of recently assimilated carbon in needles were observed, with the two TX families exhibiting higher concentrations of TNC and starch and enhanced starch partitioning compared with the ACP families. We conclude that growth differences among the four families are not a function of differences in carbon acquisition or partitioning at the leaf level.

In vivo detection and quantification of scalar coupled1H NMR resonances

In vivo1H nuclear magnetic resonance (NMR) spectroscopy is an important tool in characterizing the metabolic status of brain tissue. Changes in absolute concentrations of individual metabolites, like lactate and γ-aminobutyric acid (GABA), are important markers associated with specific brain diseases. The absolute quantification of metabolites by in vivo1H NMR is not a straightforward task, because a large number of metabolites are resonating in a small spectral region leading to severe spectral overlap. Furthermore, in vivo1H NMR is complicated by the need for complete three-dimensional spatial localization and excellent water suppression. The response of scalar-coupled spin systems to typically employed in vivo1H NMR sequences can be especially complicated. This article will review the complications of detecting and quantifying scalar-coupled spin-systems by in vivo1H NMR. The characteristics and consequences of scalar coupling will be described. The scalar coupling can be intelligently used to discriminate scalar-coupled resonances from overlapping (uncoupled) resonances by spectral editing. However, in many cases, the scalar coupling introduces complications arising from spatial localization and water suppression. The effect of typical in vivo1H NMR sequences on scalar-coupled resonances will be analyzed in detail. Finally, examples of spectral editing of GABA, lactate, and glucose will be given to describe some of the practical considerations involved with in vivo1H NMR. © 2001 John Wiley & Sons, Inc. Concepts Magn Reson 13: 32–76, 2001

Plasma renin activity, angiotensin II, prostacyclin and thromboxane A2 concentrations in 139 preeclamptic patients.

Plasma renin activity, plasma concentrations of angiotensin II (AngII), stable metabolites (6-keto-prostaglandin F1 alpha: 6-keto-PGF1 alpha) of prostacyclin (PGI2) and a metabolite (thromboxane B2: TXB2) of thromboxane A2 (TXA2) were measured with radioimmunoassay(RIA) in 107 normal pregnancy (control) and 139 preeclamptic patients in 28-41 gestational weeks. PRA and 6-keto-PGF1 alpha were significantly higher and AngII was slightly higher in preeclampsia than in control, and TXB2 was significantly lower in preeclampsia in control. The ratio of 6-keto-PGF1 alpha/TXB2 was significantly lower in preeclampsia than in control. These data suggest that the changes in the renin-angiotensin system may not be primary alterations in preeclampsia. It can be speculated that in preeclampsia the changes in absolute concentrations of 6-keto-PGF1 alpha and TXB2 are less important than the decrease in the ratio of the 6-keto-PGF1 alpha/TXB2.

Copper: Molybdenum interaction: Effect of dietary molybdenum on the binding of copper to plasma proteins in sheep

Four groups of three Blackface wethers were fed diets adequate in copper and supplemented with 0, 8, 16 or 24 μg./g. molybdenum for 203 days. All animals were then fed the unsupplemented diet for a further 21 days and blood samples were taken at intervals throughout. Sheep receiving Mo supplements up to 8 μg./g. showed no changes in plasma Cu distribution. By contrast, diets containing 16 and 24 μg./g. added Mo produced considerable changes in plasma Cu distribution, but the extent of the changes were similar for both diets. The changes produced by the diets were complete within about 12 days and when the dietary Mo supplement was withdrawn the changes were reversed in a similar period. The two higher levels of Mo supplementation produced the following changes: an increase in total plasma Cu and direct reacting Cu, no change in absolute concentration of caeruloplasmin Cu, but a decrease as a proportion of total plasma Cu. In addition it was shown that about a third of the plasma Cu was insoluble in TCA and that some of this fraction appeared to be estimated as direct reacting Cu. The significance of these findings in relation to the current concepts of the distribution of Cu within plasma and of the mechanisms of interaction of Cu and Mo is discussed.