Prolapse of semilunar cusps as causes of aortic insufficiency

Among the various anatomic classes of aortic valvular insufficiency is that associated with prolapse of one or several cusps of the valve. A number of etiologic factors come into play, including intrinsic weakness or excessive cuspid tissue, trauma, infection, inadequate support of the aorta as in certain ventricular septal defects, and loss of commissural support from laceration of the ascending aorta. The latter condition may result from trauma, cystic medial necrosis, inflammation, or hypertension. The lacerated aorta may either be associated with typical dissecting aneurysm or there may be little intramural dissection of blood.

In some instances wherein prolapse of one or more cusps causes aortic insufficiency, the functional disturbance may be overcome by correcting the basic problem while preserving the natural aortic valve.

Colour vision in blue-cone 'monochromacy'

1. Atypical (blue cone) monochromats show two action spectra when tested by the increment threshold method of Stiles with ;central' fixation. One spectrum peaks near 450 nm and has the spectral characteristics of normal blue cones. The other resembles rhodopsin (pi(0)) modified slightly by photostable macular pigment.2. Under some circumstances such observers are dichromats. There is a neutral point (matched to Illuminant ;C') in the neighbourhood of 460-470 nm.3. The spectral colour matching functions using two primaries have been measured on three such subjects. They can be fit reasonably well, although imperfectly, by linear combinations of pi(0) and pi(1). The chromaticity co-ordinates have been calculated according to the convention of W. D. Wright and compared to the results predicted from pi(0) and pi(1). The comparison suggests that part of the imperfections of the colour matching function fit is due to prereceptor differences (e.g. macular pigment) between the blue-cone monochromats and the hypothetical pi(0), pi(1) observer.4. Colour matches made at high light levels continue to hold when the intensity of the field is reduced below the cone threshold.5. Therefore one of the visual pigments participating in the colour matches has an action spectrum which is not measurably different from that of the rod pigment rhodopsin.6. Increment threshold measurements show that the mechanism which has the rhodopsin action spectrum has the directional sensitivity of cones, not rods.7. Blue test threshold during dark adaptation after a full bleach follow a bipartite exponential recovery curve. The first exponential has a time constant of 1 min, the second 2 min. By comparing these curves to the increment thresholds it is possible to relate the first to the pi(1), the second to the pi(0) cones.8. Using a broad band blue gelatin filter in the measuring light of the retinal densitometer and studying the same retinal region tested in 7 it is possible to follow the regeneration of a pigment after a full bleach which has an exponential recovery with a time constant of 1.0 min. With a yellow green filter in the measuring light the exponential recovery observed after a full bleach has a time constant of 2.0 min.9. One of the two visual pigments participating in the colour matches resides in receptors which have the action spectrum, the directional sensitivity and probably the dark adaptation curve of normal blue cones.10. The other resides in receptors which have the action spectrum of normal rods but the directional sensitivity and the dark adaptation curve of normal red and green cones.

Type II hyperlipoproteinemia in mother and twins

A 36-year-old housewife with type II hyperlipoproteinemia became pregnant with twins. Although the pregnancy was uneventful, the serum triglycerides were elevated during the third trimester, the delivery, and early puerperium. The mother had no complications directly related to the pregnancy despite hypercholesterolemia, coronary atherosclerosis, and hypertension. Cord blood cholesterol and beta lipoprotein in both twins were greater than twice normal. Despite this genetic defect in lipid transport the twins have developed normally during their first year of life. Since lipids and lipoproteins do not cross the placental barrier, it is concluded that type II hyperlipoproteinemia may have been present at birth.

Correlation of vectorcardiogram and electrocardiogram with coronary arteriogram

One hundred patients with suspected coronary heart disease were studied by vectorcardiography (VCG), electrocardiography (ECG), and coronary arteriography. Twenty-eight patients had VCG evidence of anterior infarction; 26 of this group had severe narrowing or obstruction of the left anterior descending branch. Five did not have anterior infarction by ECG. Twenty-seven patients had VCG evidence of diaphragmatic infarction; 25 of this group had severe narrowing of the right coronary artery or the left circumflex branch or both. Six of the 27 did not have ECG evidence of diaphragmatic infarction. Twelve patients had VCG evidence of posterior infarction whereas it was detected by ECG in only two. Only six of the 12, however, had severe narrowing of the nutrient arteries to the posterobasal part of the myocardium. Thirteen patients with infarction had severe narrowing but not total obstruction of a coronary artery. On the other hand, 15 patients had total obstruction of a major coronary vessel without actual infarction.

Particle-Size Analysis of Valders Drift in Eastern Wisconsin

Analysis of the fraction of Late Wisconsin deposits less than 2 mm in diameter has shown a wide range in textural composition of glacial tills. Massive lake sediments were high in clay content and contained less sand than the till of the same textural class. Glaciofluvial and eolian deposits were loamy to sandy and sandy, respectively.