Acute hemodynamic effects of red cell volume reduction in polycythemia of cyanotic congenital heart disease

Acute reduction in red cell volume (RCV) without significant alterations of blood volume in 22 patients with severe polycythemia secondary to cyanotic congenital heart disease resulted in a decrease in peripheral vascular resistance and an increase in stroke volume, systemic blood flow (SBF), and systemic oxygen transport. These changes are probably related to the decreased blood viscosity and yield shear stress associated with lower red cell concentrations. Hypervolemia in hypoxic polycythemia should be maintained in order to sustain an adequate SBF. In contrast to acute phlebotomy which may be expected to decrease blood oxygen content and SBF, the replacement of whole blood with plasma or 5% albumin is shown to result in an increased systemic blood flow and oxygen delivery.

Left ventricular pressure-volume relations and performance as affected by sudden increases in developed pressure

Left ventricular performance in the isolated dog heart was observed in a preparation in which left ventricular pressure and volume could be monitored continuously while the ventricle contracted isobarically by compressing air into a large chamber. By suddenly reducing the orifice connecting the ventricle to the chamber a constant load was imposed on the ventricle, abruptly forcing it to develop pressure in systole. This pressure increased over the ensuing 3 minutes while both the load and the end-diastolic pressure remained constant, implying that the sudden development of pressure by the ventricle was attended by a positive inotropic effect, otherwise known as homeometric autoregulation. Further studies showed this positive inotropic effect to be a function of the magnitude of the abrupt increase in systolic pressure and the time course of the experiment. β-adrenergic receptor blockade with propranolol decreased but did not abolish this effect. Infusion of norepinephrine did not enhance it. Increases in ventricular compliance that accompanied loading could not fully account for it. Evidence is presented that this positive inotropic effect may in part be mediated through the release of intrinsic catecholamines when the ventricle is forced to increase its systolic pressure.

Hydroformylation of glycals

Hydroformylation of 3,4-di-O-acetyl-d-xylal gave 4,5-di-O-acetyl-2,6-anhydro-3-deoxy-aldehydo-d-lyxo-hexose (I) and 4,5,di-O-acetyl-2,6-anhydro-3-deoxy-aldehydo-d-xylo-hexose (II). Methyl sulfoxide oxidation of 2,3-di-O-acetyl-1,5-anhydro-4-deoxy-d-arabino-hexitol (III) and of 2,3-di-O-acetyl-1,5-anhydro-l-xylo-hexitol (IV) yielded compounds I and II, respectively.Reaction of 3,4,6-tri-O-acetyl-d-glucal with carbon monoxide and hydrogen under carefully controlled conditions yielded 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-aldehydo-d-manno-heptose (VII) and 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-aldehydo-d-gluco-heptose (VIII) in a 70% yield. Compound VII was readily separated from the mixture of aldoses and alditols by column chromatography. Alternatively, aldoses VII and VIII were separated via their 2,4-dinitrophenylhydrazones. The conversion of aldoses VII and VIII into their diethyl dithioacetal derivatives is also described.The formyl group located in an equatorial orientation was found to be reduced at a faster rate than its axial counterpart.

THE STRUCTURES AND ABSOLUTE CONFIGURATIONS OF ANHYDRODEOXYHEPTITOLS

not available

REACTION OF syn-BENZALDOXIME WITH CARBON MONOXIDE AND HYDROGEN TO YIELD SUBSTITUTED UREAS

not available

THE REACTION OF UNSATURATED CARBOHYDRATES WITH CARBON MONOXIDE AND HYDROGEN: I. BRANCHED-CHAIN CARBOHYDRATE FROM 3,4,6-TRI-O-ACETYL-D-GALACTAL

A new crystalline seven-carbon branched-chain carbohydrate has been synthesized by application of the oxo reaction to 3,4,6-tri-O-acetyl-D-galactal. Periodate oxidation of the sugar alcohol was carried out to determine its structure. Crystalline benzoate and p-nitro-benzoate derivatives were obtained.

REARRANGEMENT STUDIES WITH C14: III. THE FRIEDEL–CRAFTS ALKYLATION OF ANISOLE WITH 2-PHENYLETHYL-1-C14 CHLORIDE AND 2-PHENYLETHANOL-1-C14

The Friedel–Crafts alkylation of anisole with 2-phenylethyl-1-C14 chloride and 2-phenylethanol-1-C14 resulted in a product, p-methoxydibenzyl, which showed isotope position rearrangement corresponding to an essentially 50% rearrangement of the C14 labeled atoms from the C-1 to the C-2 positions in the original chloride and alcohol. If one were to assume that both rearrangement and alkylation involve the same intermediate, these results may be explained on the basis of either an ionic mechanism for the Friedel–Crafts alkylation, the rearrangement being attributed to the formation of the phenylethyl cation, or a displacement mechanism in which the alkylation product is formed from a reaction between anisole and a rearranged polarized complex of aluminum chloride and alkylating agent. The possibility that rearrangement in the Friedel-Crafts alkylation may arise from a process separate from and prior to the alkylation stage itself is also discussed. On this basis, the intermediates involved in the rearrangement and alkylation stages will not necessarily have to be the same.

INFLUENCE OF THE NUMBER OF CARBON ATOMS OF THE ALKYL GROUP ON POLYMERIZATION AND PROPERTIES OF PARA-ALKYLPHENOL–FORMALDEHYDE POLYMERS

The polymerization (in organic media) of p-cresol–formaldehyde has been investigated in sealed tubes and in open systems. A series of almost colorless p-alkylphenol–formaldehyde polymers, prepared in sealed tubes, was studied to determine the influence of the number of carbon atoms of the substituting alkyl group on the polymerization process and on the properties of the polymers. Infrared spectra and chemical analyses of the original and heat-treated polymers were correlated with the structures of the polymers.