Near-maximal treadmill exercise testing was performed on 26 normal individuals (NL) and 78 patients with coronary artery disease (CAD) using a modified Bruce's protocol. Exercise-induced changes in orthogonal P wave measurements were made automatically, using an averaging technique, immediately before and 30sec after treadmill exercise to assess their diagnostic significance in evaluation of left ventricular (LV) function in CAD patients. The maximal inferior and posterior components of the P wave and the maximal P-vector magnitude in the frontal and left sagittal planes showed a statistically significant increase after treadmill exercise both in NL and CAD patients. These changes were considered to be physiological responses of the P wave to dynamic exercise. The percent changes of the maximal horizontal P-vector magnitude (%Hmax) were significantly higher after treadmill exercise in CAD patients than in NL. In patients with effort angina pectoris and without a previous myocardial infarction, the %Hmax showed a highly significant negative correlation with the percent changes of the LV ejection fraction (r=0.66, p<0.01), measured by exercise RI angiography. These results suggest that the exercise-induced increase in %Hmax reflects transient impairment of LV function during exercise. It was concluded that a %Hmax of more than 120% provided a useful, noninvasive index for assessing LV function in treadmill exercise testing.
This paper presents an authentication scheme for a JPEG 2000 image codestream, which is obtained by using JPEG 2000 Interactive Protocol (JPIP). JPIP allows a client to request a JPEG 2000 image that has a different representation from the original image. The client-requested image codestream is a portion of the original JPEG 2000 codestream and its structure differs for each client request. To verify the authenticity of the image requested by the client, a scalable verification mechanism is required. Hence, we propose a new scalable authentication scheme using an aggregate signature. The proposed scheme allows the scalable generation of digital signatures for any client-requested image. Simulation results show the effectiveness of the proposed scheme.
FK409 is a novel vasodilator with a unique chemical structure. We wished to elucidate the mechanisms of antianginal action of FK409 in dynamic exercise-induced angina. Twelve patients with stable effort angina pectoris were studied before and after a single 40-mg oral dose of FK409. Chest pain was induced in all of 12 patients during the control multistage bicycle ergometer exercise. After FK409 administration, the same workload did not induce chest pain in 6 patients. The ST segment at peak exercise showed less severe depression from 0.15 +/- 0.02 to 0.05 +/- 0.01 mV (p < 0.001). Left ventricular (LV) filling estimated by the Doppler method was reduced, and pulmonary artery wedge pressure decreased significantly (p < 0.001) throughout exercise testing after FK409. Myocardial oxygen uptake and coronary sinus flow throughout exercise testing decreased significantly (p < 0.05) after FK409 administration. The results of the present study demonstrate that decrease in myocardial oxygen demand may be caused by pre- and afterload reduction and that it could be a major mechanism of the antianginal action of FK409. However, other mechanisms such as redistribution of coronary blood flow to the subendocardium, direct dilatation of the stenotic parts of the epicardial arteries, and an increase in collateral blood flow should be considered additional possible mechanisms of the antianginal action of FK409.
A genetic switch determines whether the indifferent gonad develops into an ovary or a testis. In adult females of many avian species, the left ovary is functional while the right one regresses. In the embryo, bone morphogenetic proteins (BMP) mediate biological effects in many organ developments but their roles in avian sex determination and gonadal differentiation remains largely unknown. Here, we report the sex‐specific and left‐right (L‐R) asymmetric expression pattern of Bmp7 in the chicken gonadogenesis. Bmp7 was L‐R asymmetrically expressed at the beginning of genital ridge formation. After sexual differentiation occurred, sex‐specific expression pattern of Bmp7 was observed in the ovary mesenchyme. In addition, ovary‐specific Bmp 7 expression was reduced in experimentally induced female‐to‐male reversal using the aromatase inhibitor (AI). These dynamic changes of expression pattern of Bmp7 in the gonad with or without AI treatment suggest that BMP may play roles in determination of L‐R asymmetric development and sex‐dependent differentiation in the avian gonadogenesis.
During development, the eggshell supplies the majority of the calcium needed by the fowl (Gallus gallus) embryo, a finding drawn from the cumulative work of many chemical embryologists (Simkiss, 1961) and the 45calcium tracer study of Johnston & Comar (1955). This dependence on the eggshell is particularly evident when embryos are placed ex ovo in longterm shell-less culture (Dunn & Boone, 1977; Tuan, 1980a; Slavkin, Slavkin & Bringas, 1980). These cultures are produced by removing the entire content of a fertilised fowl egg from the eggshell after three days of incubation in ovo, and incubating it in a plastic sac suspended within a ringstand (Fig. 27.1) (Dunn, 1974; Dunn & Boone, 1976; Tuan, 1980a; Dunn, Fitzharris & Barnett, 1981a; Dunn, Chapter 26). These shell-less embryos develop severe systemic calcium deficiency (Tuan, 1980a; Watanabe & Imura, 1983; Narbaitz & Jande, 1983; Ono & Tuan, 1986), since their only available calcium source is the tgg yolk, which constitutes less than 20% of the total calcium found in a hatchling (Packard & Packard, 1984; Romanoff, 1967). The onset of calcium deficiency in the shell-less embryo roughly coincides with the period when shell calcium mobilisation would normally begin, around incubation days 10-12 (Terepka, Stewart & Merkel, 1969; Crooks & Simkiss, 1975; Tuan & Zrike, 1978). The hypocalcaemic state of the embryo is indicated by the significantly lowered serum calcium values (Fig. 27.2).
