This study examines the molecular form of cadmium (Cd) present in mine wastes by X‐ray Absorption Spectroscopy (XAS; Cd>20 mg/kg) using the K‐edge of Cd at the Photon Factory Advanced Ring (PF‐AR), NW10A beam line at KEK‐Tsukuba‐Japan. Mine waste materials and zinc concentrate were analyzed for Cd by ICPMS prior to undertaking XAS (range 21–452 mg/kg). Model compounds (CdO, Cd(OH)2, CdCO3, Cdacetate, CdS, Cdstearate, CdDEDTC) and samples were examined in solid form at 20 K. The XANES spectra showed similar E max values for both model compounds and samples. The EXAFS showed that Cd‐S in CdS, gives a flatter spectrum in the extended region compared to Cd‐O found with CdCO3, CdO and Cd Stearate. Linear combination fitting with model Cd compounds did not give clear assignments of composition, indicating that more detailed EXAFS spectra is required as mineral forms containing Cd were present rather than simple Cd compounds such as CdCO3. The Cd bond for a single shell model in mine waste sample matrices appears to be either Cd‐O or Cd‐S, or a combination of both. Comparison of molecular data from the XAS studies with bioaccessibility data giving a prediction of bioavailability for mine waste materials provides useful information about the significance of the cadmium form as a contaminant for health risk assessment purposes.
B1 B cells represent a unique subset of B lymphocytes distinct from conventional B2 B cells, and are important in the production of natural antibodies. A potential human homologue of murine B1 cells was defined recently as a CD20(+) CD27(+) CD43(+) cell. Common variable immunodeficiency (CVID) is a group of heterogeneous conditions linked by symptomatic primary antibody failure. In this preliminary report, we examined the potential clinical utility of introducing CD20(+) CD27(+) CD43(+) B1 cell immunophenotyping as a routine assay in a diagnostic clinical laboratory. Using a whole blood assay, putative B1 B cells in healthy controls and in CVID patients were measured. Peripheral blood from 33 healthy donors and 16 CVID patients were stained with relevant monoclonal antibodies and underwent flow cytometric evaluation. We established a rapid, whole blood flow cytometric assay to investigate putative human B1 B cells. Examination of CD20(+) CD27(+) CD43(+) cells is complicated by CD3(+) CD27(+) CD43(hi) T cell contamination, even when using stringent CD20 gating. These can be excluded by gating on CD27(+) CD43(lo-int) B cells. Although proportions of CD20(+)CD27(+)CD43(lo–int) cells within B cells in CVID patients were decreased by 50% compared to controls (P < 0·01), this was not significant when measured as a percentage of all CD27(+) B cells (P = 0·78) [corrected]. Immunophenotypic overlap of this subset with other innate-like B cells described recently in humans is limited. We have shown that putative B1 B cell immunophenotyping can be performed rapidly and reliably using whole blood. CD20(+) CD27(+) CD43(lo-int) cells may represent a distinct B1 cell subset within CD27(+) B cells. CVID patients were not significantly different from healthy controls when existing CD27(+) B cell deficiencies were taken into account.
Susceptible barley leaves show a large increase in content of free ammonium nitrogen following infection with powdery mildew. At the same time, the leaves evolve significant quantities of ammonia gas. Studies were conducted to determine whether these ions arise from an increased reduction of nitrate to ammonium, a decreased assimilation of ammonium ions, or a degradation of some compound which yields ammonia. Total pools of nitrate were relatively unchanged following infection, while nitrite remained at a constant, low level. In vitro assays revealed only a small increase in nitrate reduction by leaves (no change being detected in roots) of infected plants. Procedures were developed for measuring in vivo activities of the nitrate reducing enzyme systems; these assays also showed that nitrate reduction is not greatly increased following infection. A series of experiments v/as conducted with the enzymes of ammonium assimilation in barley leaves. Work on asparagine metabolism suggested that synthesis of this amide in barley leaves, occurs principally from aspartate and glutamine, rather than from condensation of cyanide with cysteine and subsequent hydrolysis of the reaction product. In vitro, increases were noted in the activities of NAD- and NADP- dependent glutamate dehydrogenases, glutamine synthetase and asparagine synthetase. Radiotracer experiments confirmed that there is increased synthesis of glutamate, glutamine and asparagine in infected leaves. Furthermore, powdery laildev; infection is accompanied by rises in the levels of these free amino acids, while the total content of free aspartate is decreased. Experiments in which ammonium ions and a-ketoglutarate were fed to leaves shov/ed that assimilation of the accumulated animonium ions in infected leaves is probably restricted by compartmentation. When a range of nitrogen-containing compounds was tested as possible precursors of accumulated ammonium in leaves, it was found that glutamate and particularly asparagine were potentially active. Attempts to demonstrate asparaginase activity in infected barley leaves were unsuccessful; however these leaves were shov/n to contain an asparagine - a-keto acid transaminase (which could, in part, account for the accumulation of ammonium ions through hydrolysis of its reaction product a-ketosuccinamate). Studies on the properties of enzymes in infected leaves revealed that the nitrate reductase and asparagine synthetase in these leaves were similar to those occurring in healthy tissue. The glutamine synthetase from leaves infected V7ith powdery mildew showed a decreased sensitivity to several effectors and a different response to various reaction parameters. As regards NAD-dependent glutamate dehydrogenase, the enzyme constituting the major form in infected leaves was shown to be a form differing in molecular weight (and various other physical properties) from its counterpart in non-infected leaves. Furthermore, while the latter enzym.e shows a high degree of specificity for the synthesis of glutamate, the former one has greatly i..creased ability to catalyse the oxidative deamination of gliatamate. The enzymes also differ in their regulatory (but not their kinetic) properties. The concerted action of the glutaraate dehydrogenase found in infected leaves with the asparagina - a-keto acid (a-ketoglutarate) transaminase, could explain the accumulation of ammonium ions in this tissue.
Background The measurement of monoclonal free light chains is being increasingly utilized since the introduction of serum-based assays. It is important for laboratories to determine their own reference ranges in order to reflect the local population. The aim of this study was to determine if age-adjusted reference ranges for serum free light chains would have implications for demand management of further laboratory investigations including immunofixation. Methods After certain exclusions, 4293 samples from individuals seen in primary care across Oxfordshire between 2014 and 2016 were identified for analysis of patient characteristics, serum free light chain results and estimated glomerular filtration rate. Results We found age to be an independent variable when considering serum free light chain concentrations, ratio and estimated glomerular filtration rate. The reference ranges derived from our data differ markedly from the original Binding Site ranges. When the age-specific ranges are retrospectively applied to our population, there is a 38% decrease in follow-up testing with no loss of specificity. Conclusion We feel confident implementing new age-specific serum free light chain reference ranges in our laboratory. We have developed a simple algorithm for evaluating serum free light chains based on age and estimated glomerular filtration rate. We encourage laboratories to establish their own local reference ranges using large cohorts and their chosen serum free light chain assay platform.
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