Right Internal Mammary Artery Implantation into Right Ventricular Myocardium for Revascularization of the Entire Heart: Experimental Data and Preliminary Report

The left internal mammary artery implant combined with epicardiectomy and free omental graft provides three extra-coronary sources of blood. This operation tested in dogs with 92% main-stem occlusion of three coronary arteries protected 75% of the animals. Applied clinically in over 100 patients, the operation resulted in 90% improvement. To obtain complete myocardial revascularization, the right internal mammary artery has been used as a fourth source of extra-coronary blood. In 57 animals, the right internal mammary arteries were implanted into the anterior walls of the right ventricle; in 80% this vessel formed anastomoses with the right coronary tree, and in 65% with the right and left coronary arteriolar systems. Six patients are described who underwent right internal mammary artery implantation; five of these in addition had the combined operation of left internal mammary artery implant, epicardiectomy and free omental graft. All patients had completely blocked right coronary arteries; in addition, five had advanced disease of the left coronary arterial tree.     

THE FINE STRUCTURE OF DIFFERENTIATING XYLEM ELEMENTS

Differentiating xylem elements of Avena coleoptiles have been examined by light and electron microscopy. Fixation in 2 per cent phosphate-buffered osmium tetroxide and in 6 per cent glutaraldehyde, followed by 2 per cent osmium tetroxide, revealed details of the cell wall and cytoplasmic fine structure. The localized secondary wall thickening identified the xylem elements and indicated their state of differentiation. These differentiating xylem elements have dense cytoplasmic contents in which the dictyosomes and elements of rough endoplasmic reticulum are especially numerous. Vesicles are associated with the dictyosomes and are found throughout the cytoplasm. In many cases, these vesicles have electron-opaque contents. "Microtubules" are abundant in the peripheral cytoplasm and are always associated with the secondary wall thickenings. These microtubules are oriented in a direction parallel to the microfibrillar direction of the thickenings. Other tubules are frequently found between the cell wall and the plasma membrane. Our results support the view that the morphological association of the "microtubules" with developing cell wall thickenings may have a functional significance, especially with respect to the orientation of the microfibrils. Dictyosomes and endoplasmic reticulum may have a function in some way connected with the synthetic mechanism of cell wall deposition.     

A Comparison of the Native and Derived 30S and 50S Ribosomes of Escherichia coli

Four types of ribosomes occurring in E. coli have been separated by sucrose gradient centrifugation. These are the 30S and 50S particles occurring in E. coli extracts (native particles), and the 30S and 50S particles which are the subunits of 70S ribosomes (derived particles). Two criteria were used in comparing these particles: (1) The type of RNA contained in each, as determined by sedimentation velocity in the analytical ultracentrifuge. (2) The ability of mixtures of 30S and 50S ribosomes (derived 30S + derived 50S, native 30S + native 50S) to undergo the reaction: [Formula: see text] Native and derived 30S particles were found to contain 16S RNA. Derived 50S particles contained 23S RNA and a small amount of 15 to 20S RNA, whereas native 50S ribosomes contained only 16S RNA. Derived 30S and 50S particles combined to form 70S particles. However, under identical conditions, native 30S and 50S particles did not form 70S ribosomes.     

The Chilliwack Respiratory Survey, 1963: Part I. Methodology

In order to ascertain the prevalence of chronic respiratory disease in residents of a rural town and to determine the relative importance of tobacco smoking and air pollution, a survey was conducted of 726 persons living at Chilliwack, British Columbia, in May and June, 1963. Over 95% of a random sample of adults was interviewed and performed simple tests of respiratory function. The sample was selected from a commercial census. An analysis of the demographic characteristics of the sample indicated that the group, aged 25 to 74 years, was reasonably representative for detailed study of chronic respiratory disease.     

Characterisation of neutral endopeptidase 3.4.24.11 (NEP) in the kidney: comparison between normotensive, genetically hypertensive and experimentally hypertensive rats.

Neutral endopeptidase 3.4.24.11 (NEP) has been identified as the major atrial natriuretic factor (ANF) degrading enzyme in rat kidney, therefore, suggesting a possible role for this enzyme in blood volume and pressure regulation. Various experimentally induced and genetically hypertensive rat models have been used to test NEP inhibitors. The presence of different isoforms of NEP in the various hypertensive rat models would have relevance when searching for novel NEP inhibitors. Therefore, we compared the properties of NEP in kidney cortex homogenates in order to test for possible differences in the following hypertensive rat models and their appropriate controls: spontaneously hypertensive rats (SHR), Wistar Kyoto strain (WKY), DOCA-salt hypertensive rats, and Sprague Dawley control rats (SD). No relevant differences were found when comparing the following parameters: (1) specific activity (mean: 204 U/mg protein), (2) Michaelis constant (mean: 280 microM), (3) IC50 of thiorphan (mean: 6.5 nM) and phosphoramidon (mean: 54 nM), (4) pH profiles (optimum at pH 8.0), (5) heat inactivation profiles (half-life 20 min at 65 degrees C), (6) immunotitration of kidney cortex homogenates, (7) molecular weight as determined by gel filtration (92,000 Dalton) and (8) affinity chromatography with concanavalin A. Without evidence for the presence of different NEP isoforms, it is unlikely that divergent findings in DOCA-salt rats and SHR using a given NEP inhibitor are due to isoforms of NEP.     

The atokous-epitokous border is determined before the onset of heteronereid development in Platynereis dumerilii (Annelida,Polychaeta)

Summary In most nereids sexual maturation is accompanied by a dramatic reorganization of the body that enables swarming of the formerly benthic worms. However, a border exists between unchanged anterior (atokous) and metamorphosed posterior (epitokous) segments. The site of this atokous-epitokous border (a/e border) is different in sexually mature males and females of Platynereis dumerilii. There is no correlation between the total number of setigerous segments of a specimen and the location of the a/e border. The location of the a/e border and sexual development are affected neither by cutting off caudal segments of juveniles (including the prospective a/e border) nor by transecting the ventral nerve cord. When parapodia are transplanted from prospective epitokous regions to prospective atokous regions and vice versa, they maintain their original character during metamorphosis. The results presented here suggest that prospective atokous as well as epitokous characters are determined at or only very shortly after formation of the respective segments. Thus the a/e border is established well in advance of the onset of epitokous metamorphosis.