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We investigated samples of left ventricular myocardium from Goldblatt II (4 and 8 weeks after operation) and spontaneously hypertensive rats (SHR; 40 and 80 weeks old) by histological and morphometric methods. From the same hearts, the distensibility of the left ventricular papillary muscle was analyzed by means of resting tension curves, and the collagen content of the whole left ventricular wall was determined by means of hydroxyproline concentration. In all groups, myocardial fibrosis was observed to accompany myocardial hypertrophy. The severity of fibrotic lesions increased with the duration of hypertension, and, in late stages, degenerative changes of cardiac myocytes were found. Morphometric determinations and chemical analysis of the hydroxyproline concentration revealed a decrease in myocardial muscle content, which was paralleled by an increase in collagen content when compared to the respective controls. In general, morphometric and chemical findings correlate with increased myocardial stiffness observed during mechanical measurements in isolated papillary muscle preparations from the same hearts. Differences were found, however, between chemical analysis and mechanical measurements in the 40-week-old SHR group, which may result from different patterns of collagen distribution between interstitium, perivascular spaces, and the walls of blood vessels. The comparison between histological, morphometric, chemical, and physiological data shows that (1) cardiac hypertrophy of Goldblatt and SH-rats is accompanied by myocardial fibrosis, and (2) changes in passive elastic properties of myocardium is better reflected in morphometric than in chemical analysis.

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We use the Tfm (testicular feminization) mutation of the mouse to reexamine the role of Wolffian and Müllerian ducts during formation of the vagina. Three dimensional graphical reconstructions of the lower genital tract are prepared from serial sections of male, female, and Tfm embryos from day 15 p.c. until 8 days after birth. The reconstructions show that in female and Tfm animals the caudal segments of Wolffian and Müllerian ducts fuse and migrate caudally, whereas in the male they do not fuse and remain in their original position. Following down-growth, separate Wolffian and Müllerian ducts emerge from the fused caudal tips of the ducts. The Wolffian ducts degenerate, while the Müllerian ducts fuse with each other and form the vagina. Wolffian and Müllerian ducts are connected to the urogenital sinus by the sinus ridges which in later stages are separated from the sinus by lateral furrows. The sinus ridges are replaced by the Müllerian ducts. We conclude that the vagina develops by down-growth of Wolffian and Müllerian ducts along the sinus ridges. Wolffian ducts and sinus ridges regress so that the definitive vagina is formed by the Müllerian ducts. In Tfm embryos the vagina forms as in the female but subsequently degenerates, probably due to the action of AMH. The vaginal pocket in the Tfm is the variable remainder of the vagina at the end of the degeneration process.

SUMMARY Biplane left ventricular angiography was performed in 22 patients with isolated obstructive disease of the anterior descending branch of the left coronary artery and with an anterior aneurysm following transmural myocardial infarction. Six patients were restudied between 6 and 10 months after aneurysmectomy. Left ventricular reserve was estimated by analysis of a spontaneous postextrasystolic beat. Using angiographic techniques a contractile section, a transitional section, and a noncontractile section were identified. From the surgical patients the excised aneurysm and a transmural needle biopsy of the transitional section were investigated by light microscopy. With increasing volumes of noncontractile and transitional sections, total end-diastolic volume (r = 0.81, P < 0 001) and endsystolic volume (r = 0 94, P < 0.001) increased linearly, while the ejection fraction decreased (r = 0 70, P < 0.001). No relation was found between the combined volumes of the noncontractile and transitional sections on the one hand, and the end-diastolic volume, the end-systolic volume, or the ejection fraction of the contractile section on the other hand.After ancurysmectomy a significant decrease was found in end-diastolic volume (194 to 133 ml/m2, P < 0-001) and end-systolic volume (124 to 83 ml/m2, P < 0 001) but no change occurred in ejection