Bystander activation of tissue-resident memory CD4 T cells: Getting by with a little help from unfamiliar T-cell friends

Reexposure to a pathogen triggers the activation of memory T cells that have already encountered a similar microbe. These long-lived CD4 T cells either circulate through the blood and tissues or reside within organs and are referred to as tissue-resident T cells (CD4 T_RM ). In the current issue of the European Journal of Immunology [Eur. J. Immunol. 2023. 53: 2250247] issue, Curham et al. found that tissue-resident memory CD4 T cells in the lung and nasal tissues can respond to noncognate immune challenges. CD4 T_RM cells, which were formed in response to Bordetella pertussis, proliferated and produced IL-17A in response to a secondary challenge with heat-killed Klebsiella pneumonia or lipopolysaccharide (LPS). This bystander response depends on the presence of dendritic cells that provide inflammatory cytokines. Furthermore, post K. pneumonia, intranasal immunization with whole cell pertussis vaccine reduced bacterial burden in the nasal tissue in a CD4 T-cell-dependent manner. The study indicates that the noncognate activation of T_RM may serve as an innate-like immune response that rapidly develops before establishing a new pathogen-specific adaptive immune response.

Upper airway and brain protection by plasma cells: A local affair

Protecting the upper airways and brain from viral invasion through the olfactory mucosa is critical. Wellford et al. describe a barrier that restricts the passage of circulating antibodies and prevents them from reaching the olfactory mucosa. Instead, plasma cells are recruited into this site and prevent viral infection of the airways and the brain through local antibody production.

Data-Driven Mathematical Model of Apoptosis Regulation in Memory Plasma Cells

Memory plasma cells constitutively produce copious amounts of antibodies, imposing a critical risk factor for autoimmune disease. We previously found that plasma cell survival requires secreted factors such as APRIL and direct contact to stromal cells, which act in concert to activate NF-κB- and PI3K-dependent signaling pathways to prevent cell death. However, the regulatory properties of the underlying biochemical network are confounded by the complexity of potential interaction and cross-regulation pathways. Here, based on flow-cytometric quantification of key signaling proteins in the presence or absence of the survival signals APRIL and contact to the stromal cell line ST2, we generated a quantitative model of plasma cell survival. Our model emphasizes the non-redundant nature of the two plasma cell survival signals APRIL and stromal cell contact, and highlights a requirement for differential regulation of individual caspases. The modeling approach allowed us to unify distinct data sets and derive a consistent picture of the intertwined signaling and apoptosis pathways regulating plasma cell survival.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer-reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state-of-the-art handbook for basic and clinical researchers.

Keeping up with the stress of antibody production: BAFF and APRIL maintain memory plasma cells

Memory plasma cells, also called long-lived plasma cells, provide 'humoral immunity' by continued secretion of protective antibodies against pathogens, which the immune system has once encountered. They are maintained mainly in the bone marrow, docking on to stromal cells individually. In those niches they can apparently persist for decades (Chang et al., 2018 [1]). Integrin-mediated contact to the stromal cell provides an essential survival signal to the plasma cell, activating the PI3K signalling pathway, downregulating FoxO1/3a and repressing the activation of caspases 3 and 7. In a redundant form, the cytokines BAFF and APRIL, ligands of the plasma cell receptors TACI and BCMA, provide a second essential survival signal, preventing activation of caspase 12, as triggered by endoplasmic reticulum stress.

Discrete populations of isotype-switched memory B lymphocytes are maintained in murine spleen and bone marrow

At present, it is not clear how memory B lymphocytes are maintained over time, and whether only as circulating cells or also residing in particular tissues. Here we describe distinct populations of isotype-switched memory B lymphocytes (Bsm) of murine spleen and bone marrow, identified according to individual transcriptional signature and B cell receptor repertoire. A population of marginal zone-like cells is located exclusively in the spleen, while a population of quiescent Bsm is found only in the bone marrow. Three further resident populations, present in spleen and bone marrow, represent transitional and follicular B cells and B1 cells, respectively. A population representing 10-20% of spleen and bone marrow memory B cells is the only one qualifying as circulating. In the bone marrow, all cells individually dock onto VCAM1+ stromal cells and, reminiscent of resident memory T and plasma cells, are void of activation, proliferation and mobility.

Two-dimensional gel electrophoresis of selenized yeast and autoradiography of 75Se-containing proteins

Two-dimensional high-resolution gel electrophoresis (2DE) has been applied to the fractionation of 75Se-containing proteins in yeast, grown in 75Se-containing medium, and autoradiography was used for detection of the 75Se-containing proteins. Gel filtration and ultrafiltration were used to check whether the selenium side-chains were stable in the presence of the chemicals used for lysis and 2DE. The mass distribution of the selenium-containing proteins was estimated by use of gel filtration and the results were compared with the distribution obtained by 2DE. A 2DE map of selenium-containing proteins in yeast is presented, and compared with a total protein map of yeast.

Non-ideal behaviour of free vanadate on a Superose 12 size-exclusion column. Application to in vivo 48V-labelled rat spleen homogenate

Seven chromatographic columns were evaluated for the recovery of 48V-radiolabelled vanadate. Further, the behaviour of vanadate (H2VO4-) was studied on a size-exclusion column Superose 12 as a function of (a) buffer salt molarity, (b) different buffer salts, (c) different buffers and (d) organic solvents added to the buffer. As opposed to the unsatisfactory recovery of V-compounds on other columns, we recovered the vanadium quantitatively. We observed that in most cases vanadate eluted after the total volume of the Superose 12 column. This indicates a non-ideal behaviour of vanadate. However, through this non-ideal behaviour it was possible to separate low-molecular-mass bound (Mr<5000) and unbound vanadium which would not be possible under normal behaviour. A possible explanation for this non-ideal behaviour of vanadium is put forward. The method has been successfully applied for the fractionation of different vanadium species in rat spleen homogenate.

Trends in certified reference materials for the speciation of trace elements

The measurement of the chemical species of elements (instead of the total element concentration) has become an irreversible trend in analytical chemistry. The motivation lies in the fact that the biochemical and geochemical behaviour of an element is governed by its species. Quality assurance of the analytical procedures used for speciation analysis requires the analysis of representative reference materials, certified for the relevant species. Up to now the number of existing certified reference materials for trace element species is very limited. The most important ones are environmental CRMs certified for trialkyltin compounds, methylmercury, Cr(III)/Cr(VI) and food CRMs certified for arsenic species and methylmercury. Major developments are to be expected in CRMs focussed on environmental problems, including waste treatment, on bioavailability of trace elements in food and on bio-monitoring in occupational health and hygiene. It is, however, unlikely that the producers of CRMs will ever be able to cover all needs. Add to this that many, very active species are notoriously unstable and/or short living and require in-situ analysis. This will lead to different analytical developments, such as analyses in-situ, where the classical concept of CRMs may not stand firm anymore.

The glycerol channel Fps1p mediates the uptake of arsenite and antimonite in Saccharomyces cerevisiae

The Saccharomyces cerevisiae FPS1 gene encodes a glycerol channel protein involved in osmoregulation. We present evidence that Fps1p mediates influx of the trivalent metalloids arsenite and antimonite in yeast. Deletion of FPS1 improves tolerance to arsenite and potassium antimonyl tartrate. Under high osmolarity conditions, when the Fps1p channel is closed, wild-type cells show the same degree of As(III) and Sb(III) tolerance as the fps1Delta mutant. Additional deletion of FPS1 in mutants defective in arsenite and antimonite detoxification partially suppresses their hypersensitivity to metalloid salts. Cells expressing a constitutively open form of the Fps1p channel are highly sensitive to both arsenite and antimonite. We also show by direct transport assays that arsenite uptake is mediated by Fps1p. Yeast cells appear to control the Fps1p-mediated pathway of metalloid uptake, as expression of the FPS1 gene is repressed upon As(III) and Sb(III) addition. To our knowledge, this is the first report describing a eukaryotic uptake mechanism for arsenite and antimonite and its involvement in metalloid tolerance.

In vivo distribution and speciation of [114mIn]InCl3 in the Wistar rat

Five Wistar rats were given an intraperitoneal injection of [114mIn]InCl3 during four consecutive days. One hour after the last injection the rats were sacrificed. The in vivo distribution of 114mIn was studied in the blood and in different organs. Differential centrifugation was used to study the distribution in liver, kidney and spleen homogenate. Rat serum, packed cell lysate, urine and the cytosol of liver, kidney and spleen homogenate were examined by size exclusion fast protein liquid chromatography. The results showed that serum accounts for 90% of the indium activity in whole blood. Indium is preferentially accumulated within the liver, spleen and kidney, the highest amount of 114mIn being localised in the cytosolic fraction followed by the mitochondria. Size exclusion experiments showed that, in rat serum, indium is exclusively bound to transferrin. These results differed from earlier in vitro incubation experiments of human serum with 114mIn. It was not possible, from the experiments described herein, to conclude unequivocally whether indium is bound to haemoglobin of packed cell lysate or to another high molecular mass compound. Indium is associated with the high molecular mass fraction in liver, kidney and spleen cytosol; only in kidney are small amounts of 114mIn found in the low molecular mass fraction. The in vivo inhibitory effect of indium on the delta-aminolaevulinic acid dehydratase (ALAD) enzymatic activity in red blood cells and kidney tissue, well documented by other researchers, could not be attributed to direct binding of indium with this enzyme.

Study of the binding of 114mIn radiotracer to human serum components by ultrafiltration and chromatography

The chemical speciation of indium in serum was studied. Ultrafiltration was used to investigate the influence of several buffer systems on the binding characteristics of indium in serum and to study the association of indium with transferrin and albumin. This was performed by means of batch incubation experiments with a 114mIn tracer. Different buffer systems were investigated. A series of bicarbonate, Tris:HCl and HEPES buffers were found to fit for this purpose. Phosphate buffer was not suitable, as it is capable of disrupting the binding between indium and transferrin. Batch ultrafiltration experiments with 114mIn incubated solutions of transferrin and albumin showed that both proteins are capable of binding indium to a high degree. Three chromatographic techniques (SEC, AEC, AC) were used to study the different chemically active species of indium in serum. It is concluded that next to transferrin, albumin is also responsible for the binding and transport of indium in serum.

In vitro methylation of arsenite by rabbit liver cytosol: effect of metal ions, metal chelating agents, methyltransferase inhibitors and uremic toxins

The methylation of carrier-free 74As-arsenite by liver cytosol of Flemish Giant rabbits is highly susceptible to additions of trace elements. In vitro supplementation of essential trace elements like zinc (Zn2+), vanadium (V5+), iron (Fe2+), copper (Cu2+) and selenate was shown to increase the methylation efficiency. Trivalent metal ions (e.g. Al3+, Cr3+ and Fe3+), Hg2+, Tl+ and SeO3(2-) had a deleterious effect. The inhibitory effect of EDTA, oxime and many divalent cations (Ca2+, Mg2+, Sr2+, ...) suggest a co-factor role for a specific divalent metal ion, possibly Zn2+. Chelating agents used in clinical treatment of acute and chronic inorganic arsenic poisoning lower the methylation capacity of cytosol by rendering the trivalent arsenic unavailable for the methyltransferase enzymes. S-adenosylhomocysteine and periodate-oxidized adenosine, inhibitors of s-adenosylmethionine dependent methylation pathways, inhibit the methylation of arsenite. Pyrogallol, a catechol-O-methyltransferase inhibitor, blocks the action of arsenite- and monomethylarsonic methyltransferase enzymes, suggesting a close structural relationship between the active sites of the different enzymes. Some uraemic toxins, namely oxalate, p-cresol, hypoxanthine, homocysteine and myo-inositol, inhibit arsenic methylation.

74As-arsenate metabolism in Flemish Giant rabbits with renal insufficiency

The metabolic management of carrier-free 74As-arsenate (As(V)) by uremic rabbits of the strain Flemish Giant was studied. Renal insufficiency was induced by nephrectomy of respectively 1 kidney (3/6 nephrectomy) and 1 kidney + 2/3 remaining kidney (5/6 nephrectomy). Marginal renal insufficiency developed in the 3/6 nephrectomized group, while animals of the 5/6 group became severely uremic. Renal excretion of 74As was reduced by 90% in 5/6 nephrectomized animals 4 h after intraperitoneal injection (i.p.) of the animals. The associated uremic syndrome caused a strong decrease in methylation capacity of inorganic arsenic (Asi). The second methylation step from monomethylarsonic acid (MMA) to dimethylarsinic acid (DMA) was more strongly affected than the first one, from arsenite (As(III)) to MMA. The increased availability of Asi led to more extensive binding to insoluble tissue constituents after 5/6 nephrectomy. The decreased renal reduction of As(V) led to a decrease in As(III) and an increase of As(V) and the associated As(V)-transferrin binding in plasma. Uptake of 74As-transferrin by the bone marrow might contribute to uremic anemia.

Platinum speciation in clinical and environmental samples: scrutiny of data obtained by using electrophoresis techniques (flatbed and capillary)

The commercially available and widely used flatbed electrophoresis apparatus PhastSystem and MultiPhor II (Amersham Pharmacia Biotech, Uppsala, Sweden) were checked for the possible release of significant amounts of platinum from the electrodes during isoelectric focusing (IEF) and native polyacrylamide gel electrophoresis (PAGE). Capillary electrophoresis (CE; Biofocus 3000; Bio-Rad, Munich, Germany) in zone electrophoresis (CZE) mode was investigated for the same purpose. Platinum analysis was done by inductively coupled plasma mass spectrometry (quadrupole and magnetic sector field) either "off-line" for all flatbed gels or "on-line" for the CE measurements. The buffers and process chemicals did not significantly leach platinum from the electrodes. During flatbed electrophoresis, application of the electrical field, however, released high platinum amounts exceeding by far the amount of platinum originally present in the sample. For CE, no platinum was released from the electrodes. The results are strongly dependent on the system and conditions used. The results presented in this paper underline the necessity to replace the platinum electrodes with ultrapure gold electrodes whenever investigating platinum species. Previous literature data, in which electrophoresis was used for platinum speciation without mentioning the platinum recoveries, becomes questionable.

Cadmium uptake and defense mechanism in insect cells

The uptake of cadmium and the defense mechanism against this heavy metal were studied in the Aedes albopictus C6/36 cell line. The internalization of cadmium was a very quick process and exhibited saturation kinetics over the metal concentration gradient (1.37 to 131 micromol/L). Cd toxicity and influx were both shown to be temperature dependent. The uptake was not influenced by a 2, 4-dinitrophenol pretreatment but was significantly decreased by the Ca2+ antagonist verapamil. These data suggest that cadmium is readily taken up through mediated transport, not requiring metabolic energy. A considerable amount of the metal passes through the Ca2+ channels, but probably (an)other transporting molecule(s) also play(s) an important role in the uptake process. The remarkable, nonsigmoid viability pattern of Cd-treated cultures suggests that CdCl2 concentrations above 33 micromol/L induce a cellular defense system. This phenomenon went together with increased protein synthesis. We found a major induction of a group consisting of 71-, 75-, and 78-kDa proteins, probably belonging to the HSP70 family, as similar proteins were induced by heat shock. A slight induction of a 120-kDa protein also occurred. At the highest Cd concentrations 98-, 108-, and 110-kDa proteins were induced. These data suggest that heat shock proteins may play an important role in the Aedes cell protection against Cd insult.

Dose dependent changes in 74As-arsenate metabolism of Flemish Giant rabbits

The metabolic handling of 74As-arsenate (As(V)) was studied in rabbits injected intraperitoneally (i.p.) with increasing doses of As(V) (0.00 to 1.00 mg As(V)/kg/day) over a period of 10 days. Plasma, packed cells, urine from the bladder and several tissues were analyzed for their 74As content and presence of 74As-As(V) metabolites 4 h after administration of 74As-As(V). 74As showed strong increases with increasing As(V) dose in nails and bone whereas in fat, thyroid and kidneys it decreased. Also with increasing As(V) dose, arsenate was less efficiently methylated to dimethylarsenic acid (DMA) and became more bound to insoluble tissue constituents. As a result 74As-DMA levels in tissues were systematically lower in the groups of rabbits receiving the higher doses, be it with a wide variation from one type of tissue to the other. The behaviour of 74As-monomethylarsonic acid (MMA) was different. The levels did not decrease significantly, occasionally even increased compared to the control group, indicating that especially the second methylation step is sensitive towards increasing doses of As(V). 74As-arsenite (As(III)), formed by in vivo reduction of As(V), reached maximal levels in the 0.25 mg As(V)/kg/day group as a result of the inhibited methylation. At doses > 0.25 mg As(V)/kg/day the amount of 74As-As(V) increased especially in plasma, packed cells and the urine in the bladder, indicative for a less efficient reduction of As(V).

Radiochemical neutron activation analysis in the life sciences. A look back and ahead

The contribution of radiochemical neutron activation analysis (RCNAA) to a better understanding of trace element analytics and physiology in the life sciences is outlined. Now, various non-nuclear powerful techniques for trace element analysis have become available, competing with RCNAA. This necessitates re-evaluation of the position of RCNAA, in particular versus inductively coupled plasma--mass spectrometry (ICP-MS). On basis of the characteristic features of RCNAA and the capabilities of various competing non-nuclear analytical techniques, future niches for RCNAA in the analytical market are indicated.

Speciation measurements by HPLC-HGAAS of dimethylarsinic acid and arsenobetaine in three candidate lyophilized urine reference materials

Speciation measurements of dimethylarsinic acid (DMA) and arsenobetaine (AsB) in three candidate lyophilized urine reference materials are described. The measurements were based on cation-exchange liquid chromatography coupled to hydride generation atomic absorption spectrometry with on-line digestion of the organic. As species by alkaline persulfate solution aided by ultraviolet radiation. Arsenic concentrations as DMA were significantly different in the three samples. The mean values for the three samples were 4.1 +/- 0.3, 55.3 +/- 1.2 and 134.1 +/- 1.5 micrograms l-1, respectively. No significant differences in AsB concentrations were observed among the three samples. The mean As concentrations as AsB in the three samples were 17.4 +/- 0.4, 17.7 +/- 0.2 and 17.5 +/- 0.3 micrograms l-1, respectively. By off-line digestion of the urine samples, total As concentrations in the three materials were also obtained. The mean values were 23.4 +/- 0.3, 76.6 +/- 1.6 and 151.3 +/- 1.8 micrograms l-1, respectively. These results correlated well with the results obtained by neutron activation analysis in our laboratory (r = 0.999; p < 0.0001).

Uptake of HgCl2 and MeHgCl in an insect cell line (Aedes albopictus C6/36)

We studied the uptake mechanism of mercuric chloride (Hg) and methylmercuric chloride (MeHg) in Aedes albopictus C6/36 cells. The uptake kinetics, together with the effect of temperature and a metabolic inhibitor (2, 4-dinitrophenol) on the mercury accumulation, were examined. Both amounts of internalized Hg and MeHg increased linearly with the extracellular concentration. Initially, the influx rate was high for both metal species but MeHg was found to accumulate seven times faster than Hg. At longer exposure times it leveled off for Hg, while for MeHg, the intracellular concentration decreased. Hg toxicity was not significantly influenced by elevated temperatures; in contrast there was a marked decrease of the LC50/24h value for MeHg. On the other hand, Hg accumulation was temperature dependent but MeHg was not. The different toxicity and uptake rate of both mercury compounds can be explained in terms of membrane permeability and target site. For Hg the main target seems to be the plasma membrane, while MeHg readily crosses this barrier and reacts with intracellular targets. 2, 4-Dinitrophenol had no effect on the accumulation of Hg but that of MeHg was doubled. This increased MeHg accumulation might be the result of the inhibition of an active MeHg efflux mechanism; this is in agreement with the MeHg influx kinetics. Despite these differences between Hg and MeHg, which probably result from their physicochemical properties, our experiments indicate that, for both mercury species, simple diffusion is probably the main way to entrance in Aedes cells.

Comparison between levels of trace elements in normal and cancer inoculated mice by XRF and PIXE

Determination of Rb, Br, Se, Zn, Cu, Fe, and Br/Rb ratio in tissues of mice inoculated with colon and melanoma cancer cells is described. A group of 19 Balb/c mice inoculated with C26 colon carcinoma, 4 C57B1/6 mice inoculated with B16 melanoma, and 13 control mice of both kinds were under investigation. The study was conducted on samples of blood, liver, kidneys, colon, and skin, and the trace element levels in normal and inoculated mice were compared. The inoculation was by subcutaneous injection either at the back or intrafootpad. The blood samples were taken 1, 2, and 3 wk after inoculation, and after 4 wk all the animals were sacrificed. Two nondestructive, complementary analytical methods were used: a modified X-ray fluorescence (XRF) for solid tissue and particle-induced X-ray emission (PIXE) for blood samples. The detection limit (DL) in the PIXE method was 0.35 microg/g dry wt in 600 s counting time and in XRF, 1 microg/g dry sample for Rb, Br, Se and Zn and 2 microg/g for Cu and Fe in 200 s counting time. In all the cases studied, cancerous tissue developed at the site of the injection, and a significant difference in the trace element levels was observed between tissue samples obtained from normal and inoculated mice. The most pronounced effect was an increase in Rb level in the tumor by a factor ranging between 4 and 10 relative to normal tissue, with a corresponding decrease in the Br/Rb ratio (p < 0.05). Smaller changes were found in the Br, Se, Zn, and K levels. The changes in trace element levels in the inner organs were much smaller and seem to be influenced by the site of injection.

Chemical speciation of arsenic in serum of uraemic patients

Chemical speciation of arsenic was carried out in serum of a total of 51 uraemic patients: 19 non-dialysis (ND), 18 haemodialysis (HD) and 14 continuous ambulatory peritoneal dialysis (CAPD) patients. The low molecular mass As species were separated by ion-exchange liquid chromatography and measured on-line by hydride generation atomic absorption spectrometry (HGAAS). The high molecular mass As species were separated by fast protein liquid chromatography, either size-exclusion, ion-exchange or affinity chromatography, and the fractions were digested and measured off-line with HGAAS. The mean total As concentrations in the serum of the three groups of the uraemic patients were significantly higher than the reference value (6.47 +/- 4.28, 5.12 +/- 5.58 and 4.67 +/- 5.41 micrograms l-1 for HD, ND and CAPD patients, respectively, versus the reference value of 0.96 +/- 1.52 micrograms l-1. The major As species in serum of the patients were dimethylarsinic acid (DMA) and arsenobetaine. The HD patients showed a significantly higher mean DMA level than ND and CAPD patients. No selective removal of different As species in serum of HD patients was observed after 4 h of haemodialysis. The inorganic As species in serum were bound to proteins, mainly transferrin (about 5-6% of total As in serum). This binding may play an important role in arsenic detoxification.

Study of arsenic-protein binding in serum of patients on continuous ambulatory peritoneal dialysis

Arsenic (As) bound to serum proteins in patients on continuous ambulatory peritoneal dialysis (CAPD) was studied. A prior experiment by ultrafiltration showed that 5.57% of total As was bound to serum proteins for 14 CAPD patients. Further identification of the As species and protein molecules in serum of three CAPD patients with high As concentrations was carried out by combining the separation methods of size-exclusion, anion-exchange, and affinity fast-protein liquid chromatography, detected by hydride generation atomic absorption spectrometry. The results indicated that only inorganic As species are bound to serum proteins. Transferrin is the main carrier. The concentrations of As bound to proteins in serum for the three patients were 0.44 +/- 0.12, 0.19 +/- 0.09, and 0.59 +/- 0.09 microg/L (n = 3), respectively.

Properties and Units in the Clinical Laboratory Sciences. IX. Properties and Units in Trace Elements (IUPAC-IFCC Technical report 1997). International Union of Pure and Applied Chemistry and International Federation of Clinical Chemistry. rita.cornelis@rug.ac.be

This document is the first recommendation on the presentation of trace elements and their values in clinical laboratory sciences from IFCC and IUPAC. It forms part of the ongoing effort to standardize requests and reporting of laboratory data for transmission across cultural and linguistic domains, without attempting to standardize the language used by clinicians and laboratory practitioners. Subsequent documents deal with syntax, kinds-of-property, and properties and units used in other areas of clinical laboratory sciences.

Basal metabolism of intraperitoneally injected carrier-free 74As-labeled arsenate in rabbits

The time-dependent occurrence of [74As]arsenate metabolites in Flemish Giant rabbits was investigated. As absorbed rapidly, reaching maximal concentrations in plasma and packed cells after 30 min and 2 hr, respectively. The [74As]arsenate in plasma and packed cells was reduced to [74As]arsenite, to 35 and 50% of the total 74As, respectively. The concentration of methylated As species in plasma and packed cells increased rapidly after 30 min. About 18% of total plasma 74As maximally bound to transferrin. Two-thirds of total 74As in packed cells bound to hemoglobin. Whereas little or no [74As]monomethylarsonic acid, one of the main As metabolites in humans, could be found in other animals, it is present in measurable amounts in the Flemish Giant. Furthermore, the plasma clearance rate of 74As species is lower than that in other rabbits and more similar to that of humans. The tissue 74As distribution varied widely with the highest concentrations in kidneys, liver, and lungs. 74As accumulated in bone whereas other tissues and blood showed rapid clearance rates. In muscle and heart an important part of arsenic was associated with components insoluble in phosphate-buffered isotonic saline. Binding of arsenic to soluble tissue proteins was most important in the kidneys, liver, and spleen. [74As]Arsenate metabolites were detected in all tissues. The relative amounts of [74As]arsenite or [74As]monomethylarsonic acid seldom exceeded 15% of total tissue 74As. The proportion of [74As]dimethylarsenic acid in the low molecular 74As fraction increased steadily. Substantial amounts of [74As]monomethylarsonic acid were found in the tissues..

Accumulation of arsenic species in serum of patients with chronic renal disease

Speciation of arsenic was determined in serum of 19 non-hemodialysis (non-HD) and 18 HD patients. The respective mean values of serum creatinine in these groups were 410 +/- 250 and 914 +/- 173 mumol/L (reference range for healthy subjects: females 50-80; males 57-93 mumol/L). The mean total arsenic concentrations were 5.12 +/-5.58 and 6.47 +/- 4.28 micrograms/L, respectively (reference value: 0.958 +/-1.52 micrograms/L). Dimethylarsinic acid (DMA) and arsenobetaine (AsB) were the major As species in serum of the non-HD and HD patients, with mean values of 0.82 +/- 1.05 and 1.93 +/- 1.51 micrograms/L for DMA and 3.55 +/- 4.58 and 3.47 +/- 2.89 micrograms/L for AsB, respectively. Serum concentrations of inorganic As and monomethylarsonic acid in both groups were below the detection limits for these compounds. Measurement of As concentration before vs after 4 h of HD treatment indicated that 68% of total As in serum was removed, as was 16% of the total As in packed cells. The efficiency of DMA and AsB removal during dialysis corresponded to that of total As.

Accumulation of arsenic species in serum of patients with chronic renal disease

Speciation of arsenic was determined in serum of 19 non-hemodialysis (non-HD) and 18 HD patients. The respective mean values of serum creatinine in these groups were 410 +/- 250 and 914 +/- 173 mumol/L (reference range for healthy subjects: females 50-80; males 57-93 mumol/L). The mean total arsenic concentrations were 5.12 +/-5.58 and 6.47 +/- 4.28 micrograms/L, respectively (reference value: 0.958 +/-1.52 micrograms/L). Dimethylarsinic acid (DMA) and arsenobetaine (AsB) were the major As species in serum of the non-HD and HD patients, with mean values of 0.82 +/- 1.05 and 1.93 +/- 1.51 micrograms/L for DMA and 3.55 +/- 4.58 and 3.47 +/- 2.89 micrograms/L for AsB, respectively. Serum concentrations of inorganic As and monomethylarsonic acid in both groups were below the detection limits for these compounds. Measurement of As concentration before vs after 4 h of HD treatment indicated that 68% of total As in serum was removed, as was 16% of the total As in packed cells. The efficiency of DMA and AsB removal during dialysis corresponded to that of total As.

Sample collection guidelines for trace elements in blood and urine. IUPAC Commission of Toxicology

This paper presents an organized system for element-specific sample collection and handling of human blood (whole blood, serum or plasma, packed cells or erythrocytes) and urine also indicating a proper definition of the subject and sample. Harmonized procedures for collection, preparation, analysis and quality control are suggested. The aim is to assist scientists worldwide to produce comparable data which will be useful on a regional, national and international scale. The guidelines are directed to the elements aluminium, arsenic, cadmium, chromium, cobalt, copper, lead, lithium, manganese, mercury, nickel, selenium and zinc. These include the most important elements measured for their occupational or clinical significance, and serve as examples of principles that will guide development of methods for other elements in the future.

Involvement of analytical chemistry in chemical speciation of metals in clinical samples

The different chemical species of the trace elements in a living system are determinants for their physiological behaviour. Their study is necessary to improve the understanding of trace element kinetics and metabolism. In a complex matrix, such as biological fluids and tissues, some trace elements will occur as free or mononuclear ions; other as low molecular weight complexes, as reversible or irreversible macromolecular complexes. Speciation investigations entail the separation of the compounds, followed by the measurement of the trace element in the different fractions. Frame-work-procedures are outlined and attention is drawn on the many difficulties that can be encountered. These include the complexity of the matrix, insufficient specificity of the separation of biocompounds, fortuitous contaminations with trace elements, and cutting the original metal-protein binding. State of the art description is given for the speciation studies of AI, As, Cd, Cr, Co, Cu, Hg, Ni, Pb, Pt, Se, Sn, and Zn.

Transperitoneal absorption and kinetics of chromium in the continuous ambulatory peritoneal dialysis patient--an experimental and mathematical analysis

The functional model of Cr kinetics and metabolism described by Lim et al. [Am J Physiol 1983; 224:R445-R454] for healthy people was adapted to the specific situation of the continuous ambulatory peritoneal dialysis (CAPD) patient. For this purpose 3 CAPD patients were submitted to an acute 51Cr-labelled dialysis dwell of 6 h. The rate of uptake of Cr in the plasma appeared to be equal to its disappearance rate from the peritoneal fluid. The plasma levels increased to a constant value in the first 2 h after the start of the dialysis session. The amount of Cr cumulatively excreted in the urine over the follow-up period of 10-12 days was 10-15% of the amount absorbed during the acute dwell. The experimental pharmacokinetic data were in close agreement with the values predicted by the modified functional model for Cr(III) kinetics and metabolism. According to this model, the effect of long-term CAPD treatment (10 years) should result in an accumulation of Cr with a factor of 100 in those organs, especially liver and spleen, known to have a slow exchange of Cr with the central plasma compartment. This predicted and dramatic increase was in close agreement with the Cr concentrations found in liver tissue of 3 patients who died after a variable time on CAPD.

Br, Rb, Zn, Fe, Se and K in blood of colorectal patients by INAA and PIXE

A preliminary study was conducted on blood samples and blood fractions of 11 colorectal patients and 10 healthy subjects (controls) in Belgium, in order to determine the concentration of some vital trace elements. Two non destructive analytical methods were used for the determination: INAA and PIXE. The agreement between PIXE and INAA was within about +/- 10% for plasma, but for Rb, Se and Fe in whole blood and red cells a difference of +/- 20% was noted; part of the discrepancy may be due to self absorption problems in PIXE, and for Rb, spectral interferences also may have contributed. The precision of the INAA method for the elements studied was found to be +/- 3% for whole blood and red cells and +/- 5% for plasma; the accuracy for Br, Rb and Zn was better than +/- 10% and +/- 17% for Se. The ratios of the concentrations in whole blood to red cells and whole blood to plasma were not significantly different for normals and cancer cases and, therefore, in future studies analysis of whole blood only may be sufficient. The mean values for Br, Rb, Br/Rb ratio, K, Fe and Se were significantly lower for cancer cases than for healthy individuals, and this might be applicable as an additional parameter for differentiating normals from malignant cases.

Determination of total arsenic in serum and packed cellsof patients with renal insufficiency

In order to investigate the arsenic level in serum and packed cells of patients with renal insufficiency, total arsenic (As) concentrations were determined with hydride generation atomic absorption spectrometry (HGAAS) in serum (S) and packed cells (PC) of 31 non-dialyzed patients. The accuracy of the method was tested by the analysis of arsenic in 3 certified reference materials. Patients showed a three-fold increase of arsenic concentrations in serum and a two-fold increase of arsenic in packed cells compared with controls. Patients (n=10) with higher serum creatinine (>2.0 mg/dL), urea (>0.70 g/L) and urinary protein (mean+/-SD: 1.12+/-0.82 g/L) showed higher arsenic concentrations (5.8+/-3.3 microg/L in serum and 18.0+/-16.7 microg/kg in packed cells) compared with those with lower creatinine (<1.6 mg/dL), urea (<0.6 g/L) and urinary protein (mean+/-SD: 0.27+/-0.82 g/L) (n=16, serum arsenic 1.2+/-1.2 microg/L, packed cells arsenic 2.6+/-1.9 microg/kg). The significant differences (both p < 0.001) in S and PC-arsenic levels of patients in group I and II implies a relationship between the arsenic level and the degree of chronic renal insufficiency.

Study of the chromium binding in plasma of patients on continuous ambulatory peritoneal dialysis

The distribution of chromium (Cr) among the proteins in plasma of three continuous ambulatory peritoneal dialysis (CAPD) patients and in dialysis solutions was studied with 'in vitro' and 'in vivo' 51Cr-labelled plasma. Radiolabelling allows the kinetics of newly added Cr to be investigated. The separation of the proteins was achieved by ion exchange fast protein liquid chromatography, ensuring quantitative recoveries of the 51Cr activity, transferrin and albumin. In all fractions the proteins were qualitatively characterised by iso electric focusing. The concentrations of transferrin and albumin were determined by nephelometry. The 51Cr distribution among the plasma proteins was similar for the three patients. The 51Cr activity was mainly bound to transferrin and, in the beginning of the incubation, in a lesser degree also to albumin. After 1-6 h a shift was observed of the 51Cr from albumin to an unidentified low molar mass complex (+/- 5000 Da). Two 51Cr species showed up in the subsequently drained dialysate, but they could not be identified.