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In patients who are obese or exhibit signs of pulmonary disease, standard transthoracic scanning may yield poor quality cardiac images. For these conditions, two-dimensional transesophageal echocardiography (TEE) is established as an essential diagnostic tool. Current techniques in transesophageal scanning, though, are limited by incomplete visualization of cardiac structures in close proximity to the transducer. Thus, we propose a 2D curvilinear array for 3D transesophageal echocardiography in order to widen the field of view and increase visualization close to the transducer face. In this project, a 440 channel 5 MHz two-dimensional array with a 12.6 mm aperture diameter on a flexible interconnect circuit has been molded to a 4 mm radius of curvature. A 75% element yield was achieved during fabrication and an average −6dB bandwidth of 30% was observed in pulse-echo tests. Using this transducer in conjunction with modifications to the beam former delay software and scan converter display software of the our 3D scanner, we obtained cylindrical real-time curvilinear volumetric scans of tissue phantoms, including a field of view of greater than 120° in the curved, azimuth direction and 65° phased array sector scans in the elevation direction. These images were achieved using a stepped subaperture across the cylindrical curvilinear direction of the transducer face and phased array sector scanning in the noncurved plane. In addition, real-time volume rendered images of a tissue mimicking phantom with holes ranging from 1 cm to less than 4 mm have been obtained. 3D color flow Doppler results have also been acquired. This configuration can theoretically achieve volumes displaying 180° by 120.° The transducer is also capable of obtaining images through a curvilinear stepped subaperture in azimuth in conjunction with a rectilinear stepped subaperture in elevation, further increasing the field of view close to the transducer face. Future work includes development of an array for adapting these modifications to a 6 mm diameter en do scope probe.

Five experiments were done with 34 weanling and 24 growing crossbred gilts. Individually penned pigs were fed ad libitum (expt 1) or pair-fed (expt 2 through expt 5) for either 2 (expt 1 through expt 4) or 3 (expt 5) wk. Mean body weight gain and gain/feed values were significantly (P< 0.05) greater in pigs fed carbadox (a synthetic antimicrobial). Fasting O2consumption and CO2production of pigs were measured during the 32- to 48-h (expt 1, 4 and 5) or during the 24- to 40-h (expt 2 and 3) postprandial periods with indirect open circuit calorimeters. Carbadox reduced O2consumption significantly (P< 0.05) in expt 2, but had no significant effect on CO2production in any of the five experiments. The weight of thyroid gland and the plasma concentrations of L-3,3′,5-triiodothyronine (T3) and thyroxine (T4) of pigs were not altered by carbadox. The mean weight, but not the length, of small intestine tended to be less in pigs fed carbadox. It is suggested that the growth-promoting effect of carbadox on young pigs may be associated with the weight of small intestine and its physiological processes such as metabolic rate. However, no definite effects of carbadox on whole-animal fasting metabolic rate and thyroid function could be demonstrated by the methods used in the present study.

Sixteen genetically obese (O) Duroc X Yorkshire and 16 lean (L) Hampshire X Yorkshire female pigs were randomly assigned at 4 weeks of age to dets containing 12% protein (LP) or 18% protein (C). After 8 weeks (12 weeks old) all pigs were fed diet C to slaughter at approximately 90 kg. Pigs fed LP had a slower daily gain (P< 0.01) and a lower body weight at 8 weeks (P< 0.01) than pigs fed C; O pigs had a slower daily gain than L pigs during the 8-week depletion period but the effect of the LP diet on O pigs was less than that on L pigs (P< 0.01). Blood hemoglobin and hematocrit and serum total protein, albumin and transferrin were reduced (P< 0.01) by the LP diet after 8 weeks in both genetic groups, but serum albumin was reduced more in L than in O pigs (P< 0.01); concentrations had returned to normal in both O and L pigs after 4 weeks of repletion. During repletion, L pigs previously fed LP and C diets had parallel growth curves, suggesting no compensatory growth after protein restriction. O pigs gained weight at a slower rate than L pigs during the period from 8 weeks postweaning to slaughter. Overall daily gain (depletion and repletion periods combined) was significantly greater for pigs fed C than for those fed LP during depletion period; O pigs were affected less severely than L pigs (P< 0.05). Carcass length and longissimus muscle cross-sectional area were less (P< 0.01) and back fat was greater (P< 0.01) in O than in L pigs at slaughter. It was concluded that genetically O pigs are less severely affected than L pigs by dietary protein restriction (12% protein) during the early postweaning period (4–12 weeks of age) and that repletion on a high protein diet is not associated with compensatory growth in L pigs. J. Nutr. 110: 2506-2513, 1980.