Quantification of bromide ion in biological samples using headspace gas chromatography-mass spectrometry.

OBJECTIVES: In this study, we aimed to establish a method for quantifying bromide ions (Br- ) in blood and urine using gas chromatograph-mass spectrometer (GC-MS) equipped with a headspace sampler, for biological monitoring of workers exposed to methyl bromide. METHODS: Samples were mixed with dimethyl sulfate, and Br- ions were detected using GC-MS with a headspace sampler. The validity of the proposed method was evaluated based on most of the US FDA guidance. The values obtained were compared with reference values by analysis using SeronormTM Trace Elements Whole Blood L-1 RUO. RESULTS: The calibration curve showed good linearity in the Br- concentration range of 0.1-20.0 mg/L, and the coefficient of determination R2 value was >.999. Intraday and interday accuracy values were 99.3%-103.1% and 97.4%-101.8%, respectively. The measured and reference values of Seronorm were concordant. Herein, eight urine and serum samples of workers were analyzed; the samples' Br- concentrations were known. The correlation coefficients of urine and serum samples were 0.97 and 0.96, respectively, and results were consistent. CONCLUSIONS: This study established a simple and rapid method for the determination of Br- concentration in biological samples using GC-MS with a headspace sampler. Moreover, it can be used for biological monitoring of occupational exposure to methyl bromide and for the determination of Br- concentration in a wide range of biological samples.

Zinc-containing Mohs' paste affects blood flow and angiogenesis suppression.

PURPOSE: Mohs' paste, which is composed of zinc chloride and zinc oxide starch, is used for hemostasis of superficial malignancy in the clinical setting. We investigated the concentration of intramuscular zinc in mice after Mohs' paste application and evaluated its relationship with angiogenesis from the perspective of blood flow levels within 24 h. METHODS: Male C57BL/6JJmsSlc mice were administered single dose of Mohs' paste at 25%, 50%, and 75% after unilateral hind limb surgery, and glycerin, a viscosity modifier, was administered to the control group (0%). Hind limb blood flow levels were measured with a laser Doppler perfusion imaging system (n = 6). The amounts of intramuscular zinc and vascular endothelial growth factor-A (VEGF-A) expression were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) and western blotting, respectively (n = 5 or 3). RESULTS: Blood flow levels were significantly decreased in the 50% group after 8 h, and significantly decreased in the 25% and 50% groups after 24 h. Intramuscular zinc was significantly increased in the 50% and 75% groups after 8 h. Western blotting showed that VEGF-A levels were significantly increased in the 25% and 50% groups after 8 h. Based on analytical experiments and biological investigation, we predicated the pharmacological effect of Mohs' paste and found over 50% of it is critical in the blood flow and angiogenesis suppression after more than 8 h of its application. CONCLUSIONS: The results suggest that the mechanism of blood flow suppression is independent of VEGF-A levels and might suppress future angiogenesis. Our findings support that of previous studies, in which Mohs' paste was expected to induce hemostasis and suppress angiogenesis. It is an excellent ointment that facilitates hemostasis by suppressing blood flow regardless of angiogenesis, and may be apt for situations where hemostasis is required in the clinical setting.

Assessing the chronic respiratory health risk associated with inhalation exposure to powdered toner for printing in actual working conditions: a cohort study on occupationally exposed workers over 10 years.

BACKGROUND: Little epidemiological evidence exists regarding the chronic respiratory effects of inhaled powdered toner exposure in humans, although several case reports have suggested the existence of lung disorders that might be related to exposure to toner dust. OBJECTIVE: We aimed to estimate the chronic health risk to humans associated with routine toner dust exposure in copier industry workers under current actual work conditions. DESIGN: A prospective observational cohort study of occupational population. METHODS: Changes in chest radiogram, spirometry measurements and serum and urine biomarkers of biomedical responses to extrinsic stress, as well as subjective symptoms were longitudinally observed for up to 10 years in Japanese copier industry workers responsible for the manufacturing, maintenance or recycling of powdered toner or toner-using machines. A total of 694 subjects who did not change their work category during the follow-up and were free from chronic respiratory diseases at the baseline survey provided reliable results on at least three survey occasions during 3 years or more of follow-up. RESULTS: Typical fibrosis findings associated with pneumoconiosis was not observed on chest radiograms. No significant differences associated with toner exposure were noted in the frequency of new incidence of either non-specific findings on chest radiogram or serum fibrosis biomarkers (sialylated carbohydrate antigen KL-6 and surfactant protein D). However, the exposed subjects tended to show increases in the frequency of respiratory symptoms and reduced spirometry results during the follow-up compared with the control group, although significant differences were only seen in chronic cough. CONCLUSIONS: Under the current reasonably controlled work environmental conditions, lung fibrotic changes caused by inhaled dust exposure, including powdered toner, appear to be relatively uncommon; however, non-specific temporal irritation causing subjective symptoms and inflammatory responses might exist.

Role of Hic-5 in the formation of microvilli-like structures and the monocyte-endothelial interaction that accelerates atherosclerosis.

AIMS: The adhesion of circulating monocytes to endothelial cells (ECs) is an early and critical event in the formation of atherosclerotic plaques. Hydrogen peroxide-inducible clone 5 (Hic-5) serves as an adaptor molecule in cell adhesion complexes. However, the role of endothelial Hic-5 in monocyte-EC interaction and atherogenesis remains unclear. We examined the roles of endothelial Hic-5 in monocyte-EC interaction and atherogenesis using mouse models of atherosclerosis and cultured human umbilical vein endothelial cells (HUVECs). METHODS AND RESULTS: Hic-5 was expressed in ECs, but not in monocytes/macrophages. An ex vivo monocyte adhesion assay revealed that adhesion of THP-1 monocytes to aortas isolated from Apoe(-/-) and LDLR(-/-) mice stimulated by TNF-α or oxidized LDL was suppressed by Hic-5 deficiency. Scanning electron microscopic observations of aortas harvested from Apoe(-/-) mice revealed that TNF-α- or oxidized LDL-induced microvilli-like structures were markedly suppressed by Hic-5 deficiency. Relative Hic-5 deficiency suppressed 60% of the atherosclerotic lesions in aortas from Apoe(-/-) and LDLR(-/-) mice. In contrast, overexpression of Hic-5 in HUVECs promoted induction of microvilli-like structures and adherence of THP-1 cells in an adhesion receptor such as intercellular adhesion molecule-1- and vascular cell adhesion molecule-1-dependent manner. CONCLUSION: Hic-5 in ECs plays an important role in the formation of microvilli-like structures and in the interaction between ECs and monocytes, leading to monocyte recruitment and subsequent development of atherosclerosis.

Identification of Hic-5 as a novel scaffold for the MKK4/p54 JNK pathway in the development of abdominal aortic aneurysms.

BACKGROUND: Although increased amounts of reactive oxygen species in the pathogenesis of abdominal aortic aneurysm (AAA) are well documented, the precise molecular mechanisms by which reactive oxygen species induce AAAs have not been fully elucidated. This study focused on the role of hydrogen peroxide-inducible clone 5 (Hic-5), which is induced by hydrogen peroxide and transforming growth factor-ß, in the cellular signaling of AAA pathogenesis. METHODS AND RESULTS: Using the angiotensin II-induced AAA model in Apoe(-/-) mice, we showed that Apoe(-/-)Hic-5(-/-) mice were completely protected from AAA formation and aortic rupture, whereas Apoe(-/-) mice were not. These features were similarly observed in smooth muscle cell-specific Hic-5-deficient mice. Furthermore, angiotensin II treatment induced Hic-5 expression in a reactive oxygen species-dependent manner in aortic smooth muscle cells in the early stage of AAA development. Mechanistic studies revealed that Hic-5 interacted specifically with c-Jun N-terminal kinase p54 and its upstream regulatory molecule mitogen-activated protein kinase kinase 4 as a novel scaffold protein, resulting in the expression of membrane type 1 matrix metalloproteinase and matrix metalloproteinase 2 activation in aortic smooth muscle cells. CONCLUSION: Hic-5 serves as a novel scaffold protein that specifically activates the mitogen-activated protein kinase kinase 4/p54 c-Jun N-terminal kinase pathway, thereby leading to the induction and activation of matrix metalloproteinases in smooth muscle cells and subsequent AAA formation. Our study provided a novel therapeutic option aimed at inhibiting the mitogen-activated protein kinase kinase 4-Hic-5-p54 c-Jun N-terminal kinase pathway in the vessel wall, particularly through Hic-5 inhibition, which may be used to produce more precise and effective therapies.