"Rust stain": a rare mark in firearm suicide-a case report and review of the literature.

Rust stains are marks left by firearms in case of prolonged contact with the cutaneous surfaces. These peculiar signs along with other well-documented findings can guide the medical examiner in the determination of the manner of death, especially in case of firearm suicide. This paper presents the case of a 33-year-old male soldier who committed suicide by using a short-barreled weapon, whose trigger remained in contact with the first finger of his right hand, leading to the formation of a rust stain that perfectly reproduced its design. The forensic examination of the scene, the external cadaveric inspection, and the autopsy are described. For the evaluation of the histological findings typical of rust spots, the authors decided to replicate the phenomenon in an experimental setting using porcine skin. In order to provide an exhaustive overview on the formation and the features of rust stains, a review of the forensic literature concerning this rare mark was performed.

Dysplasia features of myelodysplastic syndrome in ethnically Chinese people.

OBJECTIVE: It was our aim to study the diagnostic significances of various dysplasia characteristics in myelodysplastic syndrome (MDS). METHODS: We analyzed 160 cases of primary MDS and a control group including 28 cases of paroxysmal nocturnal hemoglobinuria (PNH), 104 cases of idiopathic thrombocytopenic purpura (ITP), 53 cases of non-severe aplastic anemia (NSAA), 40 cases of megaloblastic anemia and 50 cases of infectious and autoimmune diseases. Peripheral blood smears and bone marrow morphology were reviewed. RESULTS: There was no significant difference in the occurrence rates of a variety of dysplasias in three lineages among MDS, megaloblastic anemia and PNH; however, changes in qualities and quantities in three lineages between NSAA and MDS were significantly different. ITP and MDS showed statistical differences in multiple changes in myeloid and erythroid cells. Significant differences also existed in multiple changes in erythroid series and megakaryocytes between infectious and autoimmune diseases and MDS. Morphological abnormalities highly related with MDS included multinucleated erythroblasts, ringed sideroblasts, poikilocytosis and gigantocytes, pseudo-Pelger neutrophils, ring-shaped nucleus, and micromegakaryocytes. CONCLUSIONS: It is difficult to discriminate megaloblastic anemia and PNH from MDS by means of cell morphology. Different dysplasias of MDS have specific diagnostic values.

Construction of a SERS platform for sensitive detection of aflatoxin B1 based on CRISPR strategy.

Aflatoxin B1, a pathogen in the aflatoxin family, has attracted much attention due to the harmfulness in production and life. However, the common methods like high performance liquid chromatography used for detection of AFB1 have deficiency in complicated pretreatment processes, and the purification effect is not ideal. Herein, a SERS platform based on CRISPR strategy was designed for sensitive detection of AFB1. By synthesizing core-shell nanoparticles embedded with Raman silent region dye molecules, Prussian blue (PB), the detection of the sensor reduced background interference and the SERS signal was calibrated. At the same time, the high-efficiency reverse cleavage activity of cas12a was used to convert non-nucleic acid targets into nucleic acid, so as to achieve the effect of sensitive detection of AFB1 with a detection limit of 3.55  pg/mL. This study provides a new thought for SERS detection of non-nucleic acid targets in the future.

Brain iron accumulation in unexplained fetal and infant death victims with smoker mothers--the possible involvement of maternal methemoglobinemia.

BACKGROUND: Iron is involved in important vital functions as an essential component of the oxygen-transporting heme mechanism. In this study we aimed to evaluate whether oxidative metabolites from maternal cigarette smoke could affect iron homeostasis in the brain of victims of sudden unexplained fetal and infant death, maybe through the induction of maternal hemoglobin damage, such as in case of methemoglobinemia. METHODS: Histochemical investigations by Prussian blue reaction were made on brain nonheme ferric iron deposits, gaining detailed data on their localization in the brainstem and cerebellum of victims of sudden death and controls. The Gless and Marsland's modification of Bielschowsky's was used to identify neuronal cell bodies and neurofilaments. RESULTS: Our approach highlighted accumulations of blue granulations, indicative of iron positive reactions, in the brainstem and cerebellum of 33% of victims of sudden death and in none of the control group. The modified Bielschowsky's method confirmed that the cells with iron accumulations were neuronal cells. CONCLUSIONS: We propose that the free iron deposition in the brain of sudden fetal and infant death victims could be a catabolic product of maternal methemoglobinemia, a biomarker of oxidative stress likely due to nicotine absorption.

Prussian blue nanozyme-mediated nanoscavenger ameliorates acute pancreatitis via inhibiting TLRs/NF-κB signaling pathway.

Rationale: Acute pancreatitis (AP) is a serious acute condition affecting the abdomen and shows high morbidity and mortality rates. Its global incidence has increased in recent years. Inflammation and oxidative stress are potential therapeutic targets for AP. This study was conducted to investigate the intrinsic anti-oxidative and anti-inflammatory effects of Prussian blue nanozyme (PBzyme) on AP, along with its underlying mechanism. Methods: Prussian blue nanozymes were prepared by polyvinylpyrrolidone modification method. The effect of PBzyme on inhibiting inflammation and scavenging reactive oxygen species was verified at the cellular level. The efficacy and mechanism of PBzyme for prophylactically treating AP were evaluated using the following methods: serum testing in vivo, histological scoring following hematoxylin and eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling fluorescence staining, polymerase chain reaction array, Kyoto Encyclopedia of Genes and Genomes analysis and Western blotting analysis. Results: The synthetic PBzyme showed potent anti-oxidative and anti-inflammatory effects in reducing oxidative stress and alleviating inflammation both in vitro and in vivo in the prophylactic treatment of AP. The prophylactic therapeutic efficacy of PBzyme on AP may involve inhibition of the toll-like receptor/nuclear factor-κB signaling pathway and reactive oxygen species scavenging. Conclusion: The single-component, gram-level mass production, stable intrinsic biological activity, biosafety, and good therapeutic efficacy suggest the potential of PBzyme in the preventive treatment of AP. This study provides a foundation for the clinical application of PBzyme.

Discrepancies between the fate of myoblast xenograft in mouse leg muscle and NMR label persistency after loading with Gd-DTPA or SPIOs.

1H-NMR (nuclear magnetic resonance) imaging is regularly proposed to non-invasively monitor cell therapy protocols. Prior to transplantation, cells must be loaded with an NMR contrast agent (CA). Most studies performed so far make use of superparamagnetic iron oxide particles (SPIOs), mainly for favorable detection sensitivity. However, in the case of labeled cell death, SPIO recapture by inflammatory cells might introduce severe bias. We investigated whether NMR signal changes induced by preloading with SPIOs or the low molecular weight gadolinium (Gd)-DTPA accurately monitored the outcome of transplanted cells in a murine model of acute immunologic rejection. CA-loaded human myoblasts were grafted in the tibialis anterior of C57BL/6 mice. NMR imaging was repeated regularly until 3 months post-transplantation. Label outcome was evaluated by the size of the labeled area and its relative contrast to surrounding tissue. In parallel, immunohistochemistry assessed the presence of human cells. Data analysis revealed that CA-induced signal changes did not strictly reflect the graft status. Gd-DTPA label disappeared rapidly yet with a 2-week delay compared with immunohistochemical evaluation. More problematically, SPIO label was still visible after 3 months, grossly overestimating cell survival (<1 week). SPIOs should be used with extreme caution to evaluate the presence of grafted cells in vivo and could hardly be recommended for the long-term monitoring of cell transplantation protocols.

A simple and sensitive assay for ascorbate using potassium ferricyanide as spectroscopic probe reagent.

We have developed a rapid, inexpensive, and reliable assay to determine ascorbate using potassium ferricyanide as spectroscopic probe reagent. In this assay, Fe(III) was deoxidized to Fe(II) by ascorbate at pH 4.0 and then Fe(II) reacted with potassium ferricyanide to form a blue product, soluble Prussian blue (KFe(III)[Fe(II)(CN)6]). The absorbance of this product was monitored over time using a spectrophotometer at an absorption maximum of 735 nm and the amount of ascorbate can be calculated based on absorbance. A good linear relationship of the concentration of ascorbate versus absorbance was observed, and the linear regression equation was A=-0.01911+0.16208C (microg/ml). Moreover, the apparent molar absorption coefficient of indirect determination of ascorbate was 2.85 x 10(4) L/mol x cm. To demonstrate the usefulness of this assay, it was used to determine ascorbate in different samples, and we particularly investigated the uptake of ascorbate and ascorbate phosphate in osteoblasts. We found similar plateau levels of intracellular ascorbate at 24h for ascorbate and ascorbate phosphate. The assay was robust for a variety of samples, including orange juice, fruits, and swine plasma. The assay was quick and very economical and provides results with uncertainties on the order of only 5%.

In vivo removal of radioactive cesium compound using Prussian blue-deposited iron oxide nanoparticles.

Aim: To mitigate the side effects of medical treatment by Prussian blue (PB), a well-known adsorbent for radioactive cesium (Cs), PB-deposited magnetic nanoparticles (MNPs), were prepared and analyzed on the adsorbent capacity for Cs removal. Materials & methods: The PB-deposited MNPs were prepared by photo-deposition method and investigated for their Cs adsorption properties in vitro and in vivo. The distribution of the adsorbents was also evaluated in C57BL/6 mice. Results: PB-deposited MNPs provided an improved adsorbent capacity for Cs removal and reduced toxicity to blood cells compared with those of bulk PB. Conclusion: PB-deposited MNPs could be considered as an alternative of PB-based medicine to reduce the possible hazards caused by high dose of PB intake.

In vivo monitoring of magnetically labeled mesenchymal stem cells administered intravascularly in rat acute renal failure.

QUESTIONS UNDER STUDY: Many studies have demonstrated that mesenchymal stem cells (MSCs) contribute to the recovery of acute renal failure (ARF). The purpose of the present study was to evaluate tracking of MSCs intravascularly administered in a rat model of ARF for cellular therapy using a 1.5 T MRI system. METHODS: Fe2O3-PLL nanoparticle-labelled and unlabelled MSCs were injected into the abdominal aortas by transcatheterisation of 20 ARF rats, whose renal failure was induced by intramusclar injection of glycerol, while phosphate-buffered saline (PBS) was injected in 20 control rats. Magnetic resonance (MR) images of the kidneys were obtained, before injection of MSCs, after 1 hour, after 1, 2, and 4 days respectively. The MR imaging findings were correlated with the distribution of transplanted MSCs. The kidney injury was histologically evaluated, and the expression of proliferating cell nuclear antigen (PCNA) protein was examined. The Renal function was estimated by quantitative analysis. RESULTS: In the rat model of ARF the labelled MSCs showed a bilateral loss of signal intensity in the outer zone of the renal cortex on T2*-weighted MR images, which was visible up to 4 days after transplantation. Labelled MSCs were detected in glomerular capillaries by histological examination, the corresponding areas where signal intensity decreased in MR images. Compared to the control group, those ARF rats with MSCs injection had less renal injury, more enhanced tubular cell proliferation and better renal function. CONCLUSIONS: MR imaging visualises those intravascularly administered MSCs in vivo, which promoted recovery of ARF.

[Preparation of Prussian Blue@Yeast Catalyst and Its Heterogeneous Fenton Performance].

A novel heterogeneous Fenton catalyst, Prussian blue@yeast (PB@yeast), was prepared via facile self-assembly synthesis. The as-synthesized composite was characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). All of the results indicated that PB nanoparticles were uniformly dispersed on the surface of yeasts with stable core-shell morphology. Degradation of the model anionic fluorescent whitening agent CXT indicated that the PB@yeast catalyst presented a synergistic effect of adsorption and heterogeneous Fenton performance. Owing to the high adsorption capacity of yeast, the CXT molecules were easy to move to the active site of the catalyst, promoting the electron transfer between Fe(Ⅲ) and Fe(Ⅱ) and then enhancing the catalytic activity of the Fenton reaction effectively. Furthermore, the yeast support could improve the dispersity and stability of PB nanoparticles, which maintained excellent catalytic activity and stability after being recycled four times.