Effects of aging and antihypertensive treatment on aortic internal diameter in spontaneously hypertensive rats.

The effect of antihypertensive treatment on the development of large-artery remodeling in young animals has been widely studied, but reversal of established changes in older hypertensive animals has been largely ignored, although the latter represents a better paradigm for the human condition. We studied the effect of treatment with captopril plus hydrochlorothiazide, from 3 months onward, on geometry and wall stress of the thoracic aorta of adult (9 months, maturation) and old (15 months, senescence) spontaneously hypertensive rats; normotensive Wistar-Kyoto rats were used as controls. At 3 months of age, blood pressure, medial cross-sectional area, and internal diameter were higher in spontaneously hypertensive rats than in Wistar-Kyoto rats.

Comparison of the development of formal thought in adolescent cohorts aged 10 to 15 years (1967-1996 and 1972-1993).

Five standard Piagetian tests were administered to 180 adolescents between the ages of 10 and 15 years. The results were compared with those obtained in 1967 and in 1972 for similar participant samples. At equal ages, today's adolescents exhibited a higher level of cognitive development than the adolescents of 20 or 30 years ago.

Effect of boric acid solution on cartilage metabolism.

Pelvic cartilage of chick embryo was used to demonstrate that presence of boron in culture medium decreases synthesis of proteoglycans, collagen and total proteins but on the other hand increases the release of these macromolecules. However, when glucose concentration in culture medium is brought to 22mM, the synthesis decrease is no longer observed, whereas release increase persists. Proteins released into the culture medium included heat shock proteins (70 hsp) and tumor necrosis factor alpha (TNF alpha).

Four- and Five-Coordinate Oxovanadium(V) Alkoxides: Do Steric Effects or Electronic Properties Dictate the Geometry?

Sterically hindered ligands generally form metal complexes with lower coordination numbers than less hindered ligands. In contrast to dogma, the solid state vanadium(V) complexes with ethylene glycol and pinacol contain four- and five-coordinate vanadium atoms, respectively. Ab initio and electrostatic potential distribution calculations were conducted on both experimental and optimized geometries of the four- and five-coordinate oxovanadium chloroalkoxides.