Photon-Modulated Bond Covalency of [Sm(II)(η9-C9H9)2].

Lanthanides are widely assumed not to form covalent bonds due to the localized nature of their 4f valence electrons. This work demonstrates that the ionic bond of Sm(II) with cyclononatetraenyl (η9-C9H9-) in [Sm(η9-C9H9)2] can be modulated and becomes more covalent by photon-induced transfer of Sm 4f electrons to Sm 5d orbitals. This photon-induced change in bonding properties facilitates a subsequent reconfiguration of [Sm(η9-C9H9)2]. As a result, Sm-C bond length contraction is detected and the local Sm coordination environment exhibits more extensive disorder. Both Sm 4f and 5d electrons have increased participation in covalent Sm-ligand interactions. The Sm L3-edge valence band resonant inelastic X-ray scattering (VB-RIXS), high-resolution X-ray absorption near-edge structure (HR-XANES), and quantum chemical computations showcase a spectroscopic methodology for in-depth studies of bond covalency of lanthanide atoms.

Vertical redox zones of Fe-S-As coupled mineralogy in the sediments of Hetao Basin - Constraints for groundwater As contamination.

The formation of iron-sulfur-arsenic (Fe-S-As) minerals during biogeochemical processes in As contaminated aquifers remains poorly understood despite their importance to understanding As release and transport in such systems. In this study, X-ray absorption and Mössbauer spectroscopies complemented by electron microscopy, and chemical extractions were used to examine vertical changes of As, Fe and S speciation for the example of sediments in the Hetao Basin. Reduction of Fe(III), As(V) and SO42- species were shown to co-occur in the aquifers. Iron oxides were observed to be predominantly goethite and hematite (36 - 12%) and appeared to decrease in abundance with depth. Furthermore, reduced As (including arsenite and As sulfides) and sulfur species (including S(-II), S(-I) and S0) increased from 16% to 76% and from 13% to 44%, respectively. Iron oxides were the major As carrier in the sediments, and the lower groundwater As concentration consists with less desorbable and reducible As in the sediments. The formation of As-Fe sulfides (e.g., As containing pyrite and greigite) induced by redox heterogeneities likely contribute to localized lower groundwater As concentrations. These results help to further elucidate the complex relationship between biogeochemical processes and minerals formation in As contaminated aquifers.

Polyoxometalate chemistry at volcanoes: discovery of a novel class of polyoxocuprate nanoclusters in fumarolic minerals.

Polyoxometalate (POM) chemistry is an important avenue of comprehensive chemical research, due to the broad chemical, topological and structural variations of multinuclear polyoxoanions that result in advanced functionality of their derivatives. The majority of compounds in the polyoxometalate kingdom are synthesized under laboratory conditions. However, Nature has its own labs with the conditions often unconceivable to the mankind. The striking example of such a unique environment is volcanic fumaroles - the natural factories of gas-transport synthesis. We herein report on the discovery of a novel class of complex polyoxocuprates grown in the hot active fumaroles of the Tolbachik volcano at the Kamchatka Peninsula, Russia. The cuboctahedral nanoclusters {[MCu12O8](AsO4)8} are stabilized by the core Fe(III) or Ti(IV) cations residing in the unique cubic coordination. The nanoclusters are uniformly dispersed over the anion- and cation-deficient NaCl matrix. Our discovery might have promising implications for synthetic chemistry, indicating the possibility of preparation of complex polyoxocuprates by chemical vapor transport (CVT) techniques that emulate formation of minerals in high-temperature volcanic fumaroles.

Selenium distribution and speciation in plant parts of wheat (Triticum aestivum) and Indian mustard (Brassica juncea) from a seleniferous area of Punjab, India.

The concentration, distribution, and speciation of selenium in different parts of wheat and Indian mustard, grown in a seleniferous area in Punjab, were investigated using synchrotron based (XAS) and classical acid digestion and extraction methods. The analyses revealed a high Se enrichment in all investigated plant parts, with Se levels in the range of 133-931 mg/kg (dry weight, dw). Such high Se enrichment is mainly due to the considerable amounts of easily available Se detected in the soil, which are renewed on a yearly basis to some extent via irrigation. Speciation analysis in soil and plants indicated selenate and organic Se as major Se species taken up by plants, with a minor presence of selenite. The analyses also revealed that the highest Se enrichment occurs in the upper plant parts, in agreement with the high uptake rate and mobility of selenate within plants. In both wheat and mustard, highest Se enrichments were found in leaves (387 mg/kg·dw in wheat and 931 mg/kg·dw in mustard). Organic species (dimethylselenide and methylselenocysteine) were found in different parts of both plants, indicating that an active detoxification response to the high Se uptake is taking place through methylation and/or volatilization. The high proportion of selenate in wheat and mustard leaves (47% and 70%, respectively) is the result of the inability of the plant metabolism to completely transform selenate to non-toxic organic forms, if oversupplied. Methylselenocysteine, a common Se species in accumulating plants, was detected in wheat, suggesting that, in the presence of high Se concentration, this plant develops similar response mechanisms to accumulator plants.

Determination of placental ferritin-positive peripheral lymphocytes in early stages of breast cancer.

"Ferritin-blocked lymphocytes" or placental ferritin (PLF) -positive T cells have repeatedly been described in the circulation of patients with female breast cancer. Since a monoclonal antibody directed against PLF became available, a study was performed to evaluate its usefulness in an easily reproducible system. One hundred patients with controversial or highly suspicious findings on mammography who subsequently underwent operation entered this trial. Sixty-one healthy blood donors served as controls. Patients with early (lymph-node negative) stages of breast cancer (in situ and T1N0 tumors) revealed significantly higher numbers of PLF-positive cells (9.00% +/- 4.5% and 6.21% +/- 3.4%) as compared with controls or patients with benign lumps (p < 0.001). Patients with negative lymph nodes differed significantly from node-positive patients (9.79% versus 2.55%; p < 0.001), whereas no difference as related to menopausal and estrogen-receptor status was observed. In order to define the sensitivity and specificity of this test, we analyzed four different cutoff levels (3%, 4%, 5%, and 6% of PLF-positive T cells). At a level of PLF-positive lymphocyte cells of 4%, 94% of cancer patients with stage T1N0 disease or ductal carcinoma in situ, 5% of patients with benign lumps, and 7% of healthy controls were identified. Furthermore, 88% of all lymph node-negative cancer patients had more than 4% positive cells, compared with only 25% in patients with axillary node involvement. The fact that more than 90% of all patients with in situ carcinomas and patients with stage T1N0 cancer had values above 4% offers promising aspects for this method to be used to complement mammography in the early detection of breast cancer.

Helper-inducer and suppressor-inducer lymphocyte subsets in alcoholic cirrhosis.

Peripheral blood lymphocytes from patients with alcoholic cirrhosis, alcohol-induced fatty liver, and healthy controls were analyzed for helper-inducer (CD4+CD29w+) and suppressor-inducer (CD4+CD45R+) T lymphocytes. In confirmation of earlier reports, patients with alcoholic cirrhosis were found to have a significantly reduced absolute number of peripheral lymphocytes (p = 0.03), an elevated relative percentage of CD3+ cells (median, 76% versus 68%; p = 0.0004) and CD4+ T cells (median, 56% versus 51%; p = 0.0011), and a reduced percentage of CD8+ T lymphocytes (median, 11% versus 20%; p = 0.0007) as compared with the control group. No difference in lymphocyte subsets was observed between controls and patients with alcohol-induced fatty liver. Within the CD4+ T-cell population a change in the relative proportion of two complementary lymphocyte subsets (CD4+CD29+ helper-inducer and CD4+CD45R+ suppressor-inducer T cells) was observed in patients with alcoholic cirrhosis: a higher percentage of CD4+CD29w+ helper-inducer T cells were circulating in their peripheral blood than in healthy controls (median, 33% versus 28%; p = 0.0036), whereas the CD4+CD45R+ suppressor-inducer T-cell subset did not differ (median, 21% versus 21%) between the two groups. Owing to the reduction of lymphocyte counts in cirrhotic patients the absolute number of CD4+CD29w+ cells was not different from that of control individuals; however, CD4+CD45R+ T cells in peripheral blood (p = 0.0063) were absolutely reduced. More CD4+ cells were simultaneously CD29w+ in cirrhotic patients (61%) than in controls (52%), whereas a lower percentage of CD4+ lymphocytes was also CD45R+ in these patients (33%) as compared with controls (40%).(ABSTRACT TRUNCATED AT 250 WORDS)

Phenotypic analysis of lymphocytes involved in major histocompatibility complex unrestricted cellular cytotoxicity in patients with alcoholic cirrhosis.

Lymphocyte subpopulations known to exert major histocompatibility complex (MHC) unrestricted cytotoxicity were enumerated in 33 patients with alcoholic cirrhosis and in 10 patients with alcohol-induced fatty changes of the liver. Absolute numbers and percentages of lymphocytes bearing the CD57 (median 12 vs. 20%; p = 0.007) and CD16 (median 12 vs. 19%; p = 0.0027) antigens were significantly reduced in cirrhotic patients as compared to healthy control individuals, whereas no significant change in CD56+ cells (median 13 vs. 13%; n.s.), comprising a subpopulation with a high natural killer activity in normal individuals, was observed. A subset of these cells, cytotoxic T cells coexpressing CD56 and CD3 antigens and capable of MHC-unrestricted cellular cytotoxicity, was significantly increased in patients with alcoholic cirrhosis as compared to healthy control individuals (median 2 vs. 1%; p = 0.024). Patients with alcohol-induced fatty changes of the liver did not show any deviation of lymphocyte subpopulation from normal. The finding that lymphocyte subsets capable to exert most of the MHC-unrestricted cytotoxic capacity in peripheral blood (CD56+ non-T-cells and CD3+ CD56+ T cells) were unchanged or even increased in number suggests that the reduced natural killer cell activity known to occur in patients with alcoholic liver cirrhosis might be due to a functional defect of these cells. Furthermore, our results indicate that changes in frequency of MHC-unrestricted cytotoxic cells are not found in a similar manner in all subsets of these cells, but are dependent on the particular cell surface marker investigated.

Cellular immunodeficiency in protein-losing enteropathy. Predominant reduction of CD3+ and CD4+ lymphocytes.

Cellular immunological abnormalities were studied in a patient with protein-losing enteropathy associated with constrictive pericarditis. Analysis of lymphocyte subpopulations in peripheral blood showed lymphopenia with a decrease of CD3+ and CD4+ T cells, whereas CD8+ lymphocytes, B cells and NK cells were within the normal range. Fecal loss of lymphocytes as a cause of lymphopenia was evidenced by a marked excretion of 111-indium-labeled peripheral blood mononuclear cells via stool. Proliferative responses against several mitogens were severely reduced as was in vitro IgG production. Delayed-type hypersensitivity reaction against a variety of antigens was absent. Vaccination with tick-borne encephalitis virus, used for primary immunization, and with the recall antigen tetanus toxoid resulted in a blunted antibody response. After pericardectomy, the severity of enteric protein loss declined, serum immunoglobulin levels returned to the normal range, and total lymphocytes and CD3+ and CD4+ counts increased but remained low even 12 months after surgery. Fecal loss of lymphocytes was found to be reduced after pericardectomy, but was higher than that seen in a disease control patient with active inflammatory bowel disease. In vitro immunoglobulin production returned to normal, DTH could be demonstrated against purified protein derivative and proteus antigen, but mitogen-driven blastogenic response of lymphocytes remained low. Revaccination with tick-borne encephalitis and tetanus toxoid antigens seven months after surgery resulted in a dramatic increase of serum levels of antibodies against both antigens, comparable to that seen in healthy control individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Phenotypes of peripheral blood lymphocytes during acute hepatitis A.

We investigated peripheral blood lymphocyte phenotypes of 74 patients at weekly intervals during the course of acute hepatitis A. In the second week after onset of jaundice, a significant elevation of total lymphocytes was observed (4,096 X 10(6) +/- 1,003 X 10(6)/l vs. controls 3,038 X 10(6) +/- 1,208 X 10(6)/l, p less than 0.005). However, no change in the relative percentage of B-cells (CD20+), T-cells (CD3+ or CD2+), or T-cell subpopulations (CD4+ helper cells and CD8+ suppressor cells) could be demonstrated during the course of the disease. Activated T-cells (CD3+ DR+) were elevated during the first week (204 X 10(6) +/- 134 X 10(6)l vs. normal 91 X 10(6) +/- 54 X 10(6)/l, p less than 0.005) and during the second week (202 X 10(6) +/- 82 X 10(6)/l, p less than 0.0005) after onset of disease and returned to normal values until the third week. Cells expressing phenotypes of lymphocytes capable of exerting non-MHC-restricted cellular cytotoxicity, i.e. Natural Killer cell activity (CD57+, CD16+, and CD56+) were significantly elevated in percentage in the first week of disease, as compared to controls (CD57: 14.5 +/- 7.0% vs. 9.3 +/- 5.8%, p less than 0.05; CD16: 13.4 +/- 7.3 vs. 9.5 +/- 5.1%, p less than 0.05; CD56: 10.5 +/- 3.5% vs. 8.0 +/- 1.5%, p less than 0.005). Also the absolute numbers of these lymphocyte subpopulations were found to be elevated during the first and second week. The increase in NK cells in the initial phase of acute hepatitis A suggests an important role of these cells in the first line of defence in this disease.

Determination of placental ferritin (PLF)-positive lymphocytes in women in early stages of breast cancer.

Previous studies have proved that a certain acidic isoform of ferritin is specifically synthesized by the placenta and breast-cancer tissue. In this context it has been further reported that the determination of this so-called placental isoferritin (PLF) on the surface of a subset of peripheral lymphocytes is highly specific and sensitive for early stage breast cancer. By use of the monoclonal antibody CM-H-9 and flow cytometry, the levels of placental ferritin (PLF)-positive cells were determined in 133 female patients undergoing surgical excision of a controversial or highly suspicious lesion of the breast detected by mammography. In addition, 61 healthy blood donors served as controls. Values of PLF-positive cells in breast cancer patients differed significantly from those found in women with benign diseases and healthy controls (3.87% vs. 1.55% and 2.02, respectively; p less than 0.00001). Analysis of prognostic factors in breast cancer patients (tumor size, lymph-node status, menopausal status, estrogen receptor status, histologic grading and grading subfactors) revealed significantly higher levels of PLF-positive cells in lymph-node-negative patients compared with node-positive patients (p less than 0.00001). Furthermore, levels of PLF-positive cells showed a significantly negative correlation with tumor size and nuclear polymorphism. In 15 patients who underwent a guide-wire-directed surgical biopsy for a non-palpable, mammographically suspect lesion, 4 cases of cancer correlated with high values of PLF-positive lymphocytes while only 1 patient with a benign histologic result exhibited more than 4% positive cells.

Phagocytosis of serum-opsonized zymosan down-regulates the expression of CR3 and FcRI in the membrane of human monocytes.

The effect of iC3b receptor (CR3)-mediated phagocytosis on the expression of CR (C3b receptor, CR3) and IgG FcR (FcRI, FcRII) has been investigated by using serum-opsonized zymosan as a multivalent ligand for CR3. Sixteen hours after a short (1-h) pretreatment of human monocyte monolayers with zymosan opsonized with human AB serum (250 micrograms/ml), CR3 expression (as assessed by flow cytometric analysis with mAb Mo1) was significantly reduced by 59 +/- 3% (mean +/- SEM, n = 15, p less than 0.001). Concomitant with CR3 down modulation, FcR binding activity (as assessed by binding of IgG-coated E) was also found to be decreased to 41 +/- 4% of control (n = 7, p less than 0.001). Reduced FcR function was paralleled by a decrease in the expression of FcRI (as assessed with mAb 32.2). This FcRI modulation was not caused by zymosan-bound IgG because zymosan opsonized with agammaglobulinemic serum equally down regulated CR3 and FcRI expression. Pretreatment with zymosan opsonized with human AB serum, however, did not change the expression of other IgG and C-binding sites such as FcRII (examined with mAb IV.3 and 2E1) and CR1 (assessed with mAb 57F) as well as of unrelated cell membrane structures (beta 2m, MHC class II). In contrast, co-modulation for FcR function and CR3 expression induced by polymeric IgG is accompanied by a decreased expression of FcRII. These data indicate that interaction of a specific receptor with its ligand not only changes the expression of the receptor triggered, but has also a modulating effect on other receptor systems on the same cell.

Comparable modulation of human monocyte functions by commercial factor VIII concentrates of varying purity.

Our previous observation on immune modulation induced by a given factor VIII (F VIII) concentrate preparation was extended by showing that the immune-modulating capacity is a more general feature of F VIII products and is independent of product purity. Interaction of human monocytes with therapeutic concentrations of various F VIII concentrates (0.2 to 2 IU F VIII/mL, six different F VIII concentrates from four manufacturers) led to a significant reduction in the expression of IgG Fc receptors in the membrane of these cells (F VIII concentrate-induced downmodulation of the receptor). This Fc receptor downmodulation was achieved by a short (1-hour) incubation of human monocytes with F VIII concentrates 16 hours prior to the Fc receptor assay and did not correlate with the respective product's IgG content. Although the IgG concentrations of the different products varied greatly (from 1.0 to 177.3 mg/1,000 IU F VIII), all products behaved comparably with respect to Fc receptor downmodulation (F VIII-treated monocytes: 34% +/- 7% to 44% +/- 4% rosette-forming cells; controls in the absence of F VIII: 83% +/- 5%). Furthermore, we also were able to demonstrate that heat treatment of F VIII, now used by virtually every manufacturer to eliminate contaminating viruses, had no effect on the respective products' Fc receptor-modulating capacity. The immune-modulating component was characterized as being a high-molecular-range compound containing IgG, IgM, F VIII, and blood group substances (most likely a combination of immune complexes and immunoglobulin aggregates). This compound is present in comparable amounts in both high-purity and intermediate-purity products and apparently copurifies with F VIII during the manufacturing process.