Toxicity of Volatile Methylated Species of Bismuth, Arsenic, Tin, and Mercury in Mammalian Cells In Vitro

The biochemical transformation of mercury, tin, arsenic and bismuth through formation of volatile alkylated species performs a fundamental role in determining the environmental processing of these elements. While the toxicity of inorganic forms of most of these compounds are well documented (e.g., arsenic, mercury) and some of them are of relatively low toxicity (e.g., tin, bismuth), the more lipid-soluble organometals can be highly toxic. In the present study we investigated the cyto- and genotoxicity of five volatile metal(loid) compounds: trimethylbismuth, dimethylarsenic iodide, trimethylarsine, tetramethyltin, and dimethylmercury. As far as we know, this is the first study investigating the toxicity of volatile metal(loid) compounds in vitro. Our results showed that dimethylmercury was most toxic to all three used cell lines (CHO-9 cells, CaCo, Hep-G2) followed by dimethylarsenic iodide. Tetramethyltin was the least toxic compound; however, the toxicity was also dependend upon the cell type. Human colon cells (CaCo) were most susceptible to the toxicity of the volatile compounds compared to the other cell lines. We conclude from our study that volatile metal(loid) compounds can be toxic to mammalian cells already at very low concentrations but the toxicity depends upon the metal(loid) species and the exposed cell type

ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells in vitro

Asbestos is a known carcinogen and co-carcinogen. It is a persisting risk in our daily life due to its use in building material as asbestos-cement powder. The present study done on V79-cells (Chinese hamster lung cells) demonstrates the cytotoxic and genotoxic potential of asbestos-cement powder (ACP) in comparison with chrysotile asbestos. A co-exposure of chrysotile and ACP was tested using the cell viability test and the micronucleus assay. The kinetochore analysis had been used to analyse the pathway causing such genotoxic effects. Thiobarbituric acid-reactive substances were determined as evidence for the production of reactive oxygen species. Both, asbestos cement as well as chrysotile formed micronuclei and induced loss of cell viability in a concentration- and time- dependent way. Results of TBARS analysis and iron chelator experiments showed induction of free radicals in ACP- and chrysotile exposed cultures. CaSO(4 )appeared to be a negligible entity in enhancing the toxic potential of ACP. The co-exposure of both, ACP and chrysotile, showed an additive effect in enhancing the toxicity. The overall study suggests that asbestos-cement is cytotoxic as well as genotoxic in vitro. In comparison to chrysotile the magnitude of the toxicity was less, but co-exposure increased the toxicity of both

Does “Hidden Undercuffing” Occur Among Obese Patients? Effect of Arm Sizes and Other Predictors of the Difference Between Wrist and Upper Arm Blood Pressures

J Clin Hypertens (Greenwich). 2010;12:82–88. © 2009 Wiley Periodicals, Inc. Arm size can affect the accuracy of blood pressure (BP) measurement, and “undercuffing” of large upper arms is likely to be a growing problem. Therefore, the authors investigated the relationship between upper arm and wrist readings. Upper arm and wrist circumferences and BP were measured in 261 consecutive patients. Upper arm auscultation and wrist BP was measured in triplicate, rotating measurements every 30 seconds between sites. Upper arm BP was 131.9±20.6/71.6±12.6 mm Hg in an obese population (body mass index, 30.6±6.6 kg/m 2 ) with mean upper arm size of 30.7±5.1 cm. Wrist BP was higher (2.6±9.2 mm Hg and 4.9±6.6 mm Hg, respectively, P <.001); however, there was moderate concordance for the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) strata (κ value=0.27–0.71), and the difference was ≥5 mm Hg in 72% of the patients. The authors conclude that there was poor concordance between arm and wrist BP measurement and found no evidence that “hidden undercuffing” was associated with obesity; therefore, they do not support routine use of wrist BP measurements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78621/1/j.1751-7176.2009.00222.x.pd

Embryological stages in the establishing of myeloschisis with spina bifida

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49611/1/1000930304_ftp.pd

Indocyanine Green Angiographic Findings of Obscure Choroidal Abnormalities in Neurofibromatosis

We report two cases of choroidal neurofibromatosis, detected with the aid of indocyanine green angiography (ICGA) in patients with neurofibromatosis (NF)-1, otherwise having obscure findings based on ophthalmoscopy and fluoresceine angiography (FA). In case 1, the ophthalmoscopic exam showed diffuse bright or yellowish patched areas with irregular and blunt borders at the posterior pole. The FA showed multiple hyperfluorescent areas at the posterior pole in the early phase, which then showed more hyperfluorescence without leakage or extent in the late phase. The ICGA showed diffuse hypofluorescent areas in both the early and late phases, and the deep choroidal vessels were also visible. In case 2, the fundus showed no abnormal findings, and the FA showed weakly hypofluorescent areas with indefinite borders in both eyes. With the ICGA, these areas were more hypofluorescent and had clear borders. Choroidal involvement in NF-1 seems to occur more than expected. In selected cases, ICGA is a useful tool to be utilized when an ocular examination is conducted in a patient that has no definite findings based on the ophthalmoscope, B-scan, or FA tests

Macrocranium and macrencephaly in neurofibromatosis

Data were collected on 52 patients (30 males and 22 females) with neurofibromatosis. Using the volumetric method of Gordon, it was found that 44% of the patients had cranial capacities above the 95th percentile (70% were above the 50th percentile). The presence of intracranial tumors and/or hydrocephalus did not influence skull size. Four patients above the 95th percentile had normal pneumoencephalograms and cerebral angiograms, indicating that the cause of the macrocranium, in some instances at least, is macrencephaly. Volumetric measurement of the sella turcica in 27 of the 52 patients gave results which strongly suggest that idiopathic enlargement of the sella in neurofibromatosis is uncommon, if not rare. Skull films of 26 patients with tuberous sclerosis did not show an increase in cranial capacity similar to that found in neurofibromatosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46770/1/256_2004_Article_BF00347724.pd

Visual impairment from fibrous dysplasia in a middle-aged African man: a case report

<p>Abstract</p> <p>Introduction</p> <p>Fibrous dysplasia is a benign tumour of the bones and is a disease of unknown aetiology. This report discusses a case of proptosis and visual deterioration with associated bony mass involving the right orbit.</p> <p>Case presentation</p> <p>A 32-year-old Nigerian man of Yoruba ethnic origin presented to the eye clinic of our hospital with right-eye proptosis and visual deterioration of 7-year duration. Presentation was preceded by a history of trauma. Proptosis was preceded by trauma but was non-pulsatile with no thrill or bruit but was associated with bony orbital mass. The patient reported no weight loss. Examination of his right eye showed visual acuity of 6/60 with relative afferent pupillary defect. Fundal examination revealed optic atrophy. Computed tomography showed an expansile bony mass involving all the walls of the orbit. The bony orbital mass was diagnosed histologically as fibrous dysplasia. Treatment included orbital exploration and orbital shaping to create room for the globe and relieve pressure on the optic nerve.</p> <p>Conclusion</p> <p>Fibrous dysplasia should be considered in the differential diagnosis of slowly developing proptosis with associated visual loss in young adults.</p