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In the present study we macroscopically examined a change in the distribution of coronary atherosclerosis in cholesterol-fed rabbits. Rabbits were fed a cholesterol-enriched diet for 15 weeks, then replaced by a normal diet, and were sacrificed at 15, 24, 32 and 42 weeks after the start of the experiment. The coronary atherosclerosis in the cholesterol-fed rabbits was distributed more densely in the proximal portion than in the middle and distal portions, and the lesions were severe at 24 and 32 weeks after the start of the experiment. comparison of lesions in the three portions at these time points showed that the percentages of lesion areas in the proximal portion, the middle portion and the distal portion were approximately 51%, 21 to 25% and 0.2 to 3.7%, respectively. Macroscopic observation of the coronary atherosclerotic lesions showed that the lesions formed over the vessel lumen in the proximal portion within the range of approximately 5 mm from the orifice of the left coronary artery. In the middle portion, the lesions formed predominantly around the orifices of branches as small patchy lesions from 1 to 3 mm in diameter. These findings support previous histopathological reports that suggested that the incidence of stenosis in the proximal portion was high, and the incidence of lesion occurrence in the middle and the distal portions varied. The method, macroscopical investigation of the coronary artery, is useful for analyzing coronary atherosclerosis in the rabbit.

A simple method to quantitatively evaluate atherosclerosis in the rabbit coronary arteries by measuring macroscopic lesion areas (%) was attempted in the present study. Sixteen rabbits were fed a 0.5% cholesterol diet for 15 weeks and then 9 rabbits were sacrificed whereas the remaining 7 rabbits were maintained for further 9 weeks on a normal chow (at week 24). The left circumflex coronary arteries (LCX) were excised from the rabbit hearts under stereoscopic observation. The prepared arterial strips of LCX were 38.7 +/- 7.1 mm long and all of them reached the cardiac apex from the orifice. At week 15, the lesion area in LCX was negligible (3.2 +/- 0.4%) whereas the aortic lesions significantly developed (50.0 +/- 7.6%). At week 24, atherosclerotic lesions in both LCX and aortas increased to 32.8 +/- 9.2% and 85.9 +/- 5.6%, respectively. This is the first report that determined the luminal surface areas of atherosclerotic lesions in rabbit coronary arteries. This method may be more practical and useful for quantitative evaluation of coronary atherosclerosis in a large number of rabbits than histological observations of serial sections of rabbit hearts.

Abstract The effects of intravenous injection of purified rabbit apoA-I on the progression of aortic atherosclerosis in cholesterol-fed rabbits were examined. In experiment 1, 28 rabbits were equally divided into groups A and B and fed a 0.5% cholesterol diet for 90 days. For the last 30 days, group B received 40 mg apoA-I every week. The fatty streak lesions in group B (23.9±15.6%) were significantly suppressed compared with those in group A (46.0±24.9%) ( P P

Both the inhibitory and stimulatory guanine nucleotide-binding proteins of the adenylate cyclase complex were measured in erythrocyte membranes from patients with pseudohypoparathyroidism (PHP). The inhibitory guanine nucleotide-binding protein (Ni) of adenylate cyclase was measured by incorporation of [32P]ADP-ribose from [32P]NAD into the 39K subunit of Ni catalyzed by pertussis toxin. The ADP-ribosyltransferase activity of the toxin was expressed through incubation with dithiothreitol and erythrocyte membranes. Erythrocytes from 12 patients with PHP type I (PHP-I) had Ni values similar to those of 9 normal subjects and 2 patients with pseudopseudohypoparathyroidism. In 6 PHP-I patients, decreased activity of the stimulatory guanine nucleotide-binding protein (Ns) of adenylate cyclase, as determined by reconstitution of adenylate cyclase in the Ns-deficient membranes of cyc-S49 cells, corresponded with the reduced degree of ADP-ribosylation of the 42K subunit of Ns catalyzed by cholera toxin. These data suggest that the defect of Ns results in reduced stimulation of adenylate cyclase in some PHP-I patients, and that enhanced inhibition of the enzyme due to an increase in the 39K subunit of Ni does not account for the biochemical lesion in PHP-I patients.

Recently we recognized that pertussis toxin (PT) increased vascular permeability, as does cholera toxin. This reaction can be observed as a blueing reaction by intradermal inoculation of PT into the adult rabbit skin followed by, about 7h later, an intravenous administration of pontamine sky blue solution.The permeability factor (PF) of PT represented exact linear relationship with the dose of PT. This reaction was shown to be more sensitive than leukocytosis-promoting and histamine-sensitizing phenomena due to PT. Furthermore, above three reactions were neutralized similarly and specifically by anti-PT antibody.These results strongly suggest that the PF activity is one of the biological functions of PT, and the skin test is simple, sensitive and accurate and applicable for estimating the PT activity.