Involvement of epidermal growth factor in inducing adiposity of age female mice.

Aged mice exhibit an increase in their body weight (BW), which is associated with fat deposit increase. Epidermal growth factor (EGF) concentration in the submandibular gland also increases with aging. We examined the effects of elevated EGF on the adiposity of aged female mice. Studies were started in two groups of animals consisting of sham-operated (n = 10) and sialoadenectomized (n = 10, Sx; surgical removal of the submandibular glands) mice at 8 weeks of age. Body weight gain and food intake were measured throughout 78 weeks of age in these two groups. Body weight was significantly less in the Sx group throughout 78 weeks, while food intake was not changed by Sx after 12 weeks of age. To examine further if EGF plays a role in the induction of adiposity in aged female mice, sham-operated animals were given 100 microliters anti-EGF rabbit antiserum (anti-EGF group, n = 5) or normal rabbit serum (control group, n = 5) every 3 days, and Sx animals were given 5 micrograms/day EGF (Sx+EGF group, n = 5) or saline (Sx group, n = 5) from 78 weeks of age for 3 weeks. At 81 weeks of age, all animals of these four groups were killed, and carcass fat deposition and fat cell sizes were measured. Although the relative weights (weight ratio to BW) of the liver and kidney were not changed by Sx and anti-EGF treatment, the relative weights of mesenteric and subcutaneous fat tissues and adipocyte weights were significantly decreased in Sx and anti-EGF groups compared with the control group. Moreover, both acyl-CoA synthetase (ACS) and lipoprotein lipase (LPL) mRNA levels were significantly decreased by Sx or anti-EGF administration in mesenteric and subcutaneous fat tissues. On the other hand, EGF administration to Sx animals had no effect on BW, fat tissues and adipocyte weights, and ACS and LPL mRNA levels. The results, however, were consistent with the fact that adipose tissue EGF receptors were down regulated in Sx mice. These findings suggest that EGF may play a role in the induction of adiposity in aged female mice.

Finite-element analysis of the rotor/stator contact in a ring-type ultrasonic motor.

A way to understand mechanical characteristics of an ultrasonic motor is presented. First, the vibration mode of a stator is calculated using a finite-element method (FEM) code. The path of the elliptic motion of the stator's teeth is obtained. The computed vibration mode at the surface of the stator is compared with that measured by an electrooptical displacement transducer. Next, the contact condition of the rotor/stator is calculated. The displacement and velocity of the rotor/stator, the distortion of the stick/slip area, the rotational speed of the rotor, and the friction loss of the motor are obtained. The calculated rotor displacement and torque-rotational speed curve correspond closely to the experimentally measured ones. The internal loss of the rotor/stator and the loss of the supporting felt are measured. The total loss of these losses and the calculated friction loss agree with the measured total loss. The calculated and the measured efficiency of the motor also agree.