One of the factors postulated to drive the aging process is the accumulation of DNA damage. Here, we provide strong support for this hypothesis by describing studies of mice with a mutation in XPD, a gene encoding a DNA helicase that functions in both repair and transcription and that is mutated in the human disorder trichothiodystrophy (TTD). TTD mice were found to exhibit many symptoms of premature aging, including osteoporosis and kyphosis, osteosclerosis, early greying, cachexia, infertility, and reduced life-span. TTD mice carrying an additional mutation in XPA, which enhances the DNA repair defect, showed a greatly accelerated aging phenotype, which correlated with an increased cellular sensitivity to oxidative DNA damage. We hypothesize that aging in TTD mice is caused by unrepaired DNA damage that compromises transcription, leading to functional inactivation of critical genes and enhanced apoptosis.
Intrauterine growth retardation is presumed to be associated with decreased renal size and impaired renal function as a result of stunted kidney development and nephron deficit. To study whether very preterm birth also affects renal size at young adulthood, we sonographically measured bipolar kidney length and volume in 51 very premature individuals (<32 weeks of gestation), either small (SGA) or appropriate (AGA) for gestational age (22 SGA and 29 AGA), and 30 full-term controls 20 years after birth. Relative kidney length and volume were calculated. Both absolute and relative left kidney length and volume were significantly lower in SGA and AGA individuals, notably in women. Renal size did not differ between SGA and AGA individuals. In 70% of controls, the left kidney was larger than the right one compared with 40.9% in SGA [relative risk (RR) 1.7; 95% confidence interval (CI) 1.0−3.0] and 48.3% in AGA (RR 1.5; 95% CI 0.9−2.3) individuals. Renal structural anomalies were present in eight prematurely born participants only. Our data suggest that kidney growth is stunted after preterm birth, especially on the left side, and in the female gender.
Idiopathic infantile arterial calcification (IIAC) is a rare disease characterised by extensive depositions of hydroxyapatite in the internal elastic lamina of medium-sized and large arteries, frequently accompanied by periarticular calcifications. We report on three patients with various presenting signs and symptoms. Diagnostic imaging techniques and therapy with bisphosphonates will be discussed. For the first time long-term follow-up of up to 25 years will be reported.
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