Increased macromolecular damage due to oxidative stress in the neocortex and hippocampus of WNIN/Ob, a novel rat model of premature aging.

Wistar of the National Institute of Nutrition obese (WNIN/Ob) is a unique rat strain isolated and established at NIN, Hyderabad, India, in 1996, from its existing stock of Wistar rat colony (WNIN). This animal model exhibits all traits of metabolic syndrome and has a remarkably reduced lifespan (1.5 years as compared to 3 years in parental WNIN rats), albeit, the factors associated with premature aging are not well understood. Considering that oxidative stress and DNA damage are crucial players associated with senescence, we analyzed oxidative stress markers like lipid peroxidation and protein oxidation; DNA damage in terms of both single-stranded and double-stranded breaks and the activity of antioxidant enzymes: superoxide dismutase and catalase in brain regions of these animals. Our study revealed that the magnitude of oxidative stress and DNA damage in the neocortex and hippocampus of 3-month-old WNIN/Ob obese rats is as high as that seen in 15-month-old parental WNIN control rats. Concurrently, the antioxidant enzyme activity was significantly decreased. From these results, it can be concluded that increased oxidative stress-induced damage of macromolecules, probably due to reduced activity of antioxidant enzymes, is associated with premature aging in WNIN/Ob obese rats.

Doppler waveform patterns of the umbilical artery--screening test for high risk pregnancies.

Doppler assessment of umbilical artery waveforms using the peak systolic to end diastolic (S/D) ratio was used to determine if complications associated with impaired trophoblastic invasion of placental bed (i.e. pregnancy induced hypertension and intrauterine growth retardation) could be predicted. Values for S/D ratio of at least 4, 3.5 and 3 at 22-26, 30-32 and > or = 37 weeks gestation, respectively, were found to be better predictors of such complications. Pregnancy-induced hypertension could be predicted in 63% and growth retardation in 60% cases at 22-26 weeks of gestation.

Heart rates in the captive, free-ranging beaver.

1. Heart rates of beaver (Castor canadensis) under free-ranging captive conditions for active behaviors and resting in water (approximately 121 beats/min) were significantly (P less than 0.01) higher than for resting on land (100 beats/min). 2. Although no transient recovery tachycardia was evident in swimming heart rates following diving, average swimming heart rates were higher (127 beats/min) after diving than after other precursor behaviors (123 beats/min). 3. Beaver exhibited bradycardia when sleeping (75 beats/min), diving (61 beats/min), and when threatened on land (57 beats/min). 4. The respiratory sinus arrhythmia indicated a respiratory rate of 15 breaths/min. 5. Cold temperatures (approximately 0 degree C) elicited higher heart rates than did warmer temperatures (approximately 20 degrees C) in active, non-diving behaviors (P less than 0.05).