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Principles and Problems of Cadmium Analysis
Published in Lars Friberg, Tord Kjellström, Carl-Gustaf Elinder, Gunnar F. Nordberg, Cadmium and Health: A Toxicological and Epidemiological Appraisal, 2019
Carl-Gustaf Elinder, Birger Lind
A method for in vivo measurement of cadmium in human liver was presented by McLellan et al.44 A certain part of a person’s body is irradiated by a neutron beam. A naturally occurring isotope, 113Cd, constituting 12.3% of the metal in its native state, arrests neutrons and forms excited 114Cd isotopes. Excited 114Cd decays promptly and emits gamma rays which are detected outside the body. The intensity of the emitted gamma rays is proportional to the cadmium concentration in the liver. Mobile neutron activation equipment is now available,14,47,72 and by increasing the sensitivity of the method, it has been made possible to measure the cadmium content in the left kidney also. (The left kidney is used in order to diminish interference from the liver on the right side.) In order to obtain a correct measure of the cadmium content, the kidney must first be localized by ultrasonic scan.47 In kidney it is only possible to measure the amount, or content, of cadmium and not the concentration. Taking the weight of the kidney and the ratio between cadmium concentration in cortex and medulla, it is possible to estimate the approximate concentration of cadmium in kidney cortex, which is considered the critical organ for cadmium (Volume II, Chapters 9 and 13). An alternative method for determination of cadmium concentration in kidney cortex using X-ray-generated atomic fluorescence has also been proposed.2
Metals
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Anirudh J. Chintalapati, Frank A. Barile
The absorption of Cd varies considerably with the route of exposure. About 5–20% of orally ingested Cd salts are bioavailable, yet exposure to cadmium fumes results in up to 90% bioavailability. Once Cd is orally absorbed, it binds to albumin and alpha2-macroglobulin in serum and is distributed via systemic circulation, preferentially localizing in the liver and kidneys. Trace amounts are found in the pancreas, spleen, lung, kidneys, and testes. It is bound and sequestered by metallothionein (MT) produced in the liver, forming a cadmium–metallothionein complex (Cd-MT) that is released into the systemic circulation and undergoes glomerular filtration. The filtered Cd-MT is then reabsorbed and concentrated in proximal tubular cells, causing renal toxicity. Once formed, the Cd-MT complex is quite stable and is responsible for the extremely long biological half-life, estimated at 12–20 years.
Copper-Thiolate Proteins (Metallothioneins)
Published in René Lontie, Copper Proteins and Copper Enzymes, 1984
Weser Ulrich, Hartmann Hans-Jürgen
The electronic absorption of the MT’s is rather featureless. Apart from a weak shoulder in the UV region no further bands are detectable.39,40 Circular dichroism (CD) proved suitable to examine the contributions of the metals, the sulfur, and the polypeptide chain to the observed Cotton effects.107 From the intrinsic CD of Cd- and Zn-thionein, it follows that the protein conformation has no helical or pleated sheet conformation but has to be classified as unordered structure or “fixed random coil”. The pH dependency of the extrinsic Cotton effects was assigned to the metal-thiolate chromophore. A decrease of the stability of the metal clusters was found in the order Cu > Cd > Zn. At pH 0.44 (Cu-thionein), 3.05 (Cd-thionein), and 4.6 (Zn-thionein), respectively, half of the bound metal ions are displaced. Concomitant with the metal dissociation the CD spectra exhibited changes only in amplitude and not in shape, indicating the complete degradation of metal centers. However, spectral changes occurred by subsequent displacement of Zn by Cd (Figure 2). A shift to higher energies in the 250-nm region was observed at increasing concentrations of coordinated Cd.
Formulation and characterization of eprosartan mesylate and β-cyclodextrin inclusion complex prepared by microwave technology
Published in Drug Delivery, 2022
Abdul Ahad, Yousef A. Bin Jardan, Mohd. Zaheen Hassan, Mohammad Raish, Ajaz Ahmad, Abdullah M. Al-Mohizea, Fahad I. Al-Jenoobi
SEM image of EM per se displayed as rod shaped crystals featuring a rough surface (Figure 7(A)) (Dangre et al., 2016). The β-CD consisted of cluster structure has a globular shape particle with irregular sizes (Alshehri et al., 2020). While in the SEM scan of PM, distinctive EM crystals, which were mingled with β-CD crystals or cohered to their surface, were apparently discovered (Figure 7(C)). On the other hand, in the EM/β-CD inclusion complex (Figure 7(D)) displayed as irregular particles in which the characteristic surface morphology of EM and β-CD melted and reduced size amorphous particles having irregular size and shape were clearly visible. Inclusion complex image demonstrated that the particles of the inclusion complex were physically different from the morphology of individual excipients and their PM, which have supported the formation of the inclusion complex (Naidu et al., 2004).
Metagenomic analysis of the human microbiome reveals the association between the abundance of gut bile salt hydrolases and host health
Published in Gut Microbes, 2020
Baolei Jia, Dongbin Park, Yoonsoo Hahn, Che Ok Jeon
BA metabolism, which primarily involves hydrolysis and 7α/β-dehydroxylation reactions, is associated with many human diseases.22 Our results showed that BSH gene abundance is associated with IBDs, CA, and CRC (Figure 3). In the present study, the decreased abundance of Cluster 2 BSH genes observed in CD conditions is consistent with a previous study.28 We further showed that the abundance of Cluster 1 and Cluster 3 BSH genes is enhanced in the IBDs. These results are in accordance with the two well-established IBD-associated taxonomic signatures: (i) phylum-level decrease in Firmicutes, and (ii) phylum-level increase in Proteobacteria,29 since the BSHs in Cluster 2 are predominantly from Firmicutes, while the BSHs in Clusters 1 and 3 are predominantly from Proteobacteria. Furthermore, our analysis from six independent studies in seven countries indicated that the abundance of Cluster 2 BSH genes, predominantly of Firmicutes, is associated with CRC, which was consistent with the previous studies that showed that Firmicutes were significantly depleted in the gut microbiome of CRC patients.30,31 Taken together, these analyses suggest that the abundance of BSHs is highly related with gastrointestinal diseases.
Research progress of self-assembled nanogel and hybrid hydrogel systems based on pullulan derivatives
Published in Drug Delivery, 2018
Tao Zhang, Ruyi Yang, Shengnan Yang, Jibin Guan, Dong Zhang, Yan Ma, Hongzhuo Liu
In addition to the graft of organic agents, combinations with inorganic substances may produce a novel nanomaterial (Sugawara et al., 2006; Yamane et al., 2008; Katagiri et al., 2013; Tsuchido et al., 2015). For instance, organic–inorganic hybrid nanogels with dual network structures were prepared by condensation of silanol groups grafted to CHP. They showed a narrow particle size distribution of approximately 90 nm in diameter, and colloidal stability in the presence of methyl-β-CD (Yamane et al., 2008). Another exciting development is that the coordination of zinc ions contributed to the successful preparation of protein nanogels using vitamin B6 (pyridoxal)-bearing pullulan as a bio-crosslinker and anionic bovine serum albumin (BSA) as a model protein (Tsuchido et al., 2015).