Tribute to Dr Louis Keith: Twin and Physician Extraordinaire/Twin Research Reports: Influences on Asthma Severity; Chimerism Revisited; DNA Strand Break Repair/Media Reports: Twins Born Apart; Elevated Twin Frequencies; Celebrity Father of Twins; Conjoined Twinning

The International Society for Twin Studies has lost a valued friend and colleague. Dr Louis Keith, Emeritus Professor of Obstetrics and Gynecology at Northwestern University, in Chicago, passed away on Sunday, July 6, 2014. His life and work with twins will be acknowledged at the November 2014 International Twin Congress in Budapest, Hungary. Next, twin research reports on the severity of asthma symptoms, a case of chimerism, and factors affecting DNA breakage and repair mechanisms are reviewed. Media reports cover twins born apart, elevated twin frequencies, a celebrity father of twins, and a family's decision to keep conjoined twins together.

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Identification by microscopically controlled comet assay of peritoneal macrophages in a mixture of peritoneal exudate for DNA strand break analysis

Mutation Research/Genetic Toxicology and Environmental Mutagenesis ◽

10.1016/s1383-5718(98)00190-9 ◽

1999 ◽

Vol 439 (2) ◽

pp. 171-181 ◽

Cited By ~ 7

Author(s):

C Bock ◽

A Dube ◽

K.O Greulich ◽

P.K Gupta

Keyword(s):

Comet Assay ◽

Strand Break ◽

Peritoneal Macrophages ◽

Peritoneal Exudate ◽

Dna Strand Break ◽

Dna Strand

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The invariance of the total direct DNA strand break yield

Medical Physics ◽

10.1118/1.3597568 ◽

2011 ◽

Vol 38 (7) ◽

pp. 4147-4153 ◽

Cited By ~ 38

Author(s):

M. A. Bernal ◽

C. E. deAlmeida ◽

C. Sampaio ◽

S. Incerti ◽

C. Champion ◽

...

Keyword(s):

Strand Break ◽

Dna Strand Break ◽

Dna Strand ◽

Break Yield

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Particle characterization and toxicity in C57BL/6 mice following instillation of five different diesel exhaust particles designed to differ in physicochemical properties

10.21203/rs.3.rs-18458/v1 ◽

2020 ◽

Author(s):

Katja Maria Bendtsen ◽

Louise Gren ◽

Vilhelm Berg Malmborg ◽

Pravesh Chandra Shukla ◽

Martin Tunér ◽

...

Keyword(s):

Physicochemical Properties ◽

Diesel Exhaust ◽

Strand Break ◽

Diesel Exhaust Particles ◽

Ultra Low Sulfur Diesel ◽

Dna Strand Break ◽

Diesel Particles ◽

Exhaust Particles ◽

Dna Strand ◽

Low Sulfur

Abstract Background Diesel exhaust is carcinogenic and exposure to diesel particles cause health effects. We investigated the toxicity of diesel exhaust particles designed to have varying physicochemical properties in order to attribute health effects to specific particle characteristics. Particles from three fuel types were compared at 13% engine intake O 2 concentration: MK1 ultra low sulfur diesel (DEP13) and the two renewable diesel fuels hydrotreated vegetable oil (HVO13) and rapeseed methyl ester (RME13). Additionally, diesel particles from MK1 ultra low sulfur diesel were generated at 9.7% (DEP9.7) and 17% (DEP17) intake O 2 concentration. We evaluated physicochemical properties and histopathological, inflammatory and genotoxic responses on day 1, 28 and 90 after single intratracheal instillation in mice compared to reference diesel particles and carbon black.Results Moderate variations were seen in physical properties for the five particles: primary particle diameter: 15-22 nm, specific surface area: 152-222 m 2 /g, and count median mobility diameter: 55-103 nm. Larger differences were found in chemical composition: organic carbon/total carbon ratio (0.12-0.60), polycyclic aromatic hydrocarbon content (1-27 mg/mg) and acid-extractable metal content (0.9-16 mg/mg). Intratracheal exposure to all five particles induced similar toxicological responses, with different potency. Lung particle retention was observed in DEP13 and HVO13 exposed mice on day 28, with less retention for the other fuel types. RME exposure induced limited response whereas the remaining particles induced dose-dependent inflammation and acute phase response on day 1. DEP13 induced acute phase response on day 28 and inflammation on day 90. DNA strand break levels were not increased as compared to vehicle, but were increased in lung and liver compared to blank filter extraction control. Neutrophil influx on day 1 correlated best with estimated deposited surface area, but also with elemental carbon, organic carbon and PAHs. DNA strand break levels in liver on day 90 correlated with acellular particle-induced ROS.Conclusions We studied diesel exhaust particles designed to differ in physicochemical properties. Our study highlights particle size, elemental carbon content, PAHs and ROS-generating potential as physicochemical predictors of diesel particle toxicity.

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