The "valve" of the ductus arteriosus--an enigma.

The urine/plasma creatinine ratio (U/P Cr), the urine sodium concentration (UNa), and the diuretic response to mannitol infusion in 23 patients were reviewed in an attempt to differentiate functional renal failure (FRF) from acute tubular necrosis (ATN). FRF was diagnosed if the plasma urea nitrogen (PUN) or serum creatinine stabilized within 72 hours. When renal failure persisted longer, patients had ATN. Subjects dying within 72 hours were excluded. Ten patients had ATN and five survived. The minimum duration of renal failure among survivors was 10 days. None responded to mannitol. Of 13 patients with FRF, 11 survived. Seven of 12 who received mannitol responded with a diuresis. The mean UNa in the patients with ATN was 51.4 mEq./1. ± 9.48 (SE). The mean U/P Cr was 11.2 ± 1.12. In patients with FRF, the mean UNa was 14.0 mEq./1. ± 4.2 and the mean U/P Cr was 42.5 ± 11.5. A significant overlap was present between the two groups. When UNa was factored by the U/P Cr, the resultant ratio was significantly different for the two groups of patients (P < 0.01), and this proved to be a useful clinical index with which to distinguish FRF from established ATN.     

The "activated" hepatic glucocorticoid-receptor complex. Its generation and properties.

The glucocorticoid receptor-glucocorticoid complex of the hepatic cytosol need undergo an "activation" to enable its binding to nuclei, chromatin, or stripped DNA. The conditions of this activation have been studied using native calf thymus DNA absorbed to cellulose. At low ionic strength, activation is very slow at 0 degrees, but, takes place rapidly at 25 degrees, reaching completion at 1 hour. Addition of 10 mm CaCl2 or 150 mm NaCl increases the rate of activation of the receptor at 0 degrees. Neither magnesium nor manganese ions can replace calcium with respect to enabling activation of the steroid-receptor complex to occur at low temperatures. Isofocusing studies reveal that the major component of the unactivated steroid-receptor complex has an isoelectric point of 7.1. Incubation of the steroid-receptor complex at 25 degrees for 30 min leads to its conversion to a form with an isoelectric point of 6.1 concurrent with the development of its ability to bind to DNA-cellulose. Sucrose density gradient analysis reveals that no detectable alteration in the sedimentation coefficient of the steroid-receptor complex occurs during its activation. MnCl2 (20mm) effeciently precipitates the unactivated hormone-receptor complex and to a lesser degree, precipitates the activated hormone-receptor complex.     

The "falcifolia" syndrome of Oenothera. First communication

Summary Reciprocal crosses between Oe. lamarckiana and Oe. suaveolens lead to an off-spring, part of which is crippled. According to Harte 1948 this characteristic malformation is called falcifolia (sickle-shaped leaf). It is restricted to certain sectors of the plant and appears in various plants at different stages of their development. For this reason the percentage of falcifolia-plants increases gradually during the vegetative period. Reciprocal crosses show a clear quantitative difference in regard to the percentage of crippled plants as well as to the degree of crippling. At maturity the percentage of falcifolia-plants is approximately as follows: Oe. lamarckianaxOe. suaveolens: 90–100% Oe. suaveolensxOe. lamarckiana: 20–40% Selfing of normal and crippled hybrids leads to an F₂ which consists of both types; the percentage varies. In general a crippled plant produces more falcifolia-progeny than a normal plant. Backcrossing with Oe. lamarckiana leads to an offspring with less than 20% falcifolia whilst backcrossing with Oe. suaveolens produces more than 50% crippled plants. This large difference appears in every backcross, regardless whether the F₁-plant is normal or crippled, and whether it functions as seed-parent or pollen-parent. Furthermore it does not matter whether the F₁ has been obtained with Oe. lamarckiana or with Oe. suaveolens as seed-parent. The peculiar inheritance appears to be independent of nuclear and plastid genes (genome and plastome), but is in fact a non-mendelian one. Falcifolia cannot be produced by grafting Oe. lamarckiana and Oe. suaveolens reciprocally. It seems to be caused by the interaction of different plasmotypes.

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Herrn Professor Dr. Dr. h. c. Friedrich Oehlkers zum 80. Geburtstag gewidmet.     

The "crown" excision of facial skin lesions.

We present a method for local excision of facial skin lesions adjacent to the esthetic boundaries of the face.     

The structure of human lipoprotein A-I. Evidence for the "belt" model.

The two main competing models for the structure of discoidal lipoprotein A-I complexes both presume that the protein component is helical and situated around the perimeter of a lipid bilayer disc. However, the more popular "picket fence" model orients the protein helices perpendicular to the surface of the lipid bilayer, while the alternative "belt" model orients them parallel to the bilayer surface. To distinguish between these models, we have investigated the structure of human lipoprotein A-I using a novel form of polarized internal reflection infrared spectroscopy that can characterize the relative orientation of protein and lipid components in the lipoprotein complexes under native conditions. Our results verify lipid bilayer structure in the complexes and point unambiguously to the belt model.