Septal Margins Research Articles

The anatomy of the pulmonary vascular bed in the toad Bufo marinus.

1. The pulmonary vascular anatomy of the toad, Bufo marinus was studied by scanning electron microscopy of vascular corrosion casts and of tissues prepared for light microscopy. 2. The lung is divided by septa into three orders of alveoli. Arterial branches run in the septa and cannot be observed directly through the lung surface. 3. The capillary bed forms a meshwork over the lumenal surface of septa and lung walls. It is divided into longitudinal zones of arterial distribution; it is broken along primary septal margins into primary alveolar units; within alveoli, it is functionally divided by distortion over circum-alveolar smooth muscle bundles. 4. The capillaries form a network of tubes rather than a perforated sheet of vascular space. Capillary beds on either face of septa are interconnected through the septum. 5. There is no evidence of collateral ("bronchial") vessels or of anatomically definable shunt vessels. 6. Intrinsic pulmonary arterial branches have a muscular coat.

Biosystematic Studies onMaianthemum (Liliaceae-Polygonatae)

A similar floral vascular anatomy involving a constant dimerous, bicarpellate plan for each of the threeMaianthemum species is reported. All of the tepal, stamen and ovary traces are derived via repeated radial division of two pedicel bundles. The four tepal and stamen traces are fusion products, as are the two dorsals. A third, smaller (vestigial) pedicel bundle which continues unbranched and uninvolved into the ovary was observed in all three species. It could indicate a past reduction from a trimerous, tricarpellate condition, and gives a basis for comparison to the closely related genusSmilacina. The gynoecial vasculature lacks peripheral laterals, septal axials and terminal cross-connections between the dorsal and ventral supplies. The placentation is only apparently axile, since the two septa divide at the mid-ovary level. Consistently the four co-lateral ovules which are anatropous and bitegmic are supplied by four free placentals. The placentals supplying the two ovules of a given carpel have had a common origin in a single pedicel bundle. Raphides characterize post-fertilization ovaries in all species. ADrusa-type of embyro sac formation shown forM. dilatatum corresponds with that known for the other species. An internal stigmoidal tissue system involving micropylar obturators extends from the base of each locule through the hollow stylar canal. Temporal separation occurs between male and female meiosis (protandry), and outbreeding is further promoted by terminal septal glands functioning as nectaries and the synchronized closure of the common carpellary cavity by inter-digitating papillae on the inner septal margins.

マイズルソウ属の進化生物学的研究

A similar floral vascular anatomy involving a constant dimerous, bicarpellate plan for each of the threeMaianthemum species is reported. All of the tepal, stamen and ovary traces are derived via repeated radial division of two pedicel bundles. The four tepal and stamen traces are fusion products, as are the two dorsals. A third, smaller (vestigial) pedicel bundle which continues unbranched and uninvolved into the ovary was observed in all three species. It could indicate a past reduction from a trimerous, tricarpellate condition, and gives a basis for comparison to the closely related genusSmilacina. The gynoecial vasculature lacks peripheral laterals, septal axials and terminal cross-connections between the dorsal and ventral supplies. The placentation is only apparently axile, since the two septa divide at the mid-ovary level. Consistently the four co-lateral ovules which are anatropous and bitegmic are supplied by four free placentals. The placentals supplying the two ovules of a given carpel have had a common origin in a single pedicel bundle. Raphides characterize post-fertilization ovaries in all species. ADrusa-type of embyro sac formation shown forM. dilatatum corresponds with that known for the other species. An internal stigmoidal tissue system involving micropylar obturators extends from the base of each locule through the hollow stylar canal. Temporal separation occurs between male and female meiosis (protandry), and outbreeding is further promoted by terminal septal glands functioning as nectaries and the synchronized closure of the common carpellary cavity by inter-digitating papillae on the inner septal margins.

Atrial septal defects of the secundum type

Summary Small interauricular shunts can be tolerated by the human heart through a long life and hence do not require surgical clcsure. In contrast, large interauricular shunts in which pulmonary blood flow is elevated considerably above that through periphery of the body should be subjected to surgical closure of the septal opening. The methods which we prefer to use in accomplishing such repair include employment of a pump oxygenator under normothermic conditions, use of extracorporeal circulation, cardiopulmonary by-pass, and approach to the congenital anomaly through the right auricle. In most instances a primary closure can be attained; occasionally it is necessary to use onlay of some foreign material to patch over defects which are very large or which have septal margins which are very thin. Postoperative observations on surgically-treated patients have shown striking improvements in health and in cardiao function; physiologic studies have demonstrated marked reduction in work of the right ventricle. These results can be obtained at a surgical risk which is very low. It is clear that surgical closure of an interauricular septal defect should be undertaken before vascular changes have appeared or have reached any troublesome degree. In a series of 166 patients operated upon for atrial septal defect, in 28 of whom there were also anomalies of drainage of pulmonary veins, the surgical mortality from all causes was 3.6 per cent. In patients in whom there was no associated mitral disease or pre-existing failure, the operative mortality was virtually zero.