Partitioning of pulmonary resistance during constriction in the dog: effects of volume history

We assessed the relative changes in airways and lung tissue with bronchoconstriction, and the changes in each during and following a deep inhalation (DI). We partitioned pulmonary resistance (RL) into airway (Raw) and tissue (Vtis) components using alveolar capsules in 10 anesthetized, paralyzed, and open-chested dogs ventilated sinusoidally with 350-ml breaths at 1 Hz. We made measurements before and during bronchoconstriction induced by vagal stimulation or inhalation of histamine or prostaglandin F2 alpha (PGF2 alpha), each of which decreased dynamic compliance by approximately 40%. With histamine and PGF2 alpha the rise in RL was predominantly due to Vtis. With vagal stimulation there was a relatively greater increase in Raw than Vtis. At higher lung volumes, Vtis increases offset falls in Raw, producing higher RL at these volumes before and during constriction with PGF2 alpha and histamine. During constriction with vagal stimulation, the fall in Raw with inflation overrode the rise in Vtis, resulting in a lower RL at the higher compared with the lower lung volume. The changes seen after a DI in the control and constricted states were due to alterations in tissue properties, both viscous and elastic. However, the relative hysteresis of the airways and parenchyma were equal, since Raw, our index of airway size, was unchanged after a DI.

Assessment of genetic and nongenetic influences on pulmonary function. A twin study

To better understand the extent to which familial similarities in pulmonary function (PF) are attributable to genetic rather than to shared environmental influences, we studied the twinship aggregation of PF in 256 monozygotic (MZ) and 158 dizygotic (DZ) adult twin members of the Greater Boston Twin Registry. Genetic influences on various spirometric measures were estimated with twinship intrapair correlations adjusted using a regression model to control for similarities in the anthropomorphic characteristics of twins, and for the effects of a number of environmental factors that included childhood respiratory illness, occupational dust exposure, and smoking history. A significant influence of smoking on all air-flow measures was observed in this population for whom genetic similarities were adjusted. However, highly significant adjusted intrapair correlations for all spirometric measures, ranging from 0.52 to 0.76, were observed for the MZ twins. The intrapair correlations for the DZ twins were approximately one-half the magnitude of those for the MZ twins. These data suggest that a large proportion of the measured variability in PF may be accounted for by genetic influences other than those associated with body size.

Acidité de Brønsted des phosphoranes à liaison P—H; identification de leurs bases conjuguées; détermination de leur pKa

The P—H proton of phosphoranes containing an α-hydroxy acid or iminodiacetic acid ligand is sufficiently mobile to be removed at room temperature by medium strength bases such as triethylamine. The deprotonation products identified by 31P nmr are (a) the phosphoranide for the bicyclic compound prepared from iminodiacetic acid, (b) the anionic phosphite isomeric to the above, for phosphoranes containing the α-hydroxy acid ligand, (c) the phosphite and the phosphoramide in equilibrium, for phosphoranes containing two α-hydroxy ligands. The pKa values potentiometrically determined in DMF solution by titration of the phosphoranes with triethylamine correspond to weak or mild acids. However, the phosphoranes studied are more acid in DMF than other known compounds containing the P—H bond. They are also more dissociated in this solvent than carboxylic acids. [Journal translation]

Propriétés nucléophiles des phosphoranures

The reaction of various bases with P—H bond-containing phosphoranes bearing α-hydroxy acid, α-aminoacid, or iminodiacetic acid ligands leads to the formation of phosphoronates which react with electrophiles such as alkyl halides, phenyl azide, carbon disulfide, orthoquinones, or keto-acids. New phosphoranes and hexacoordinated phosphorus compounds could thus be prepared. [Journal translation]

Therapeutic use of adenosine for terminating spontaneous paroxysmal supraventricular tachycardia

Intravenous adenosine proved effective in eight out of ten episodes of acute spontaneous supraventricular tachycardia. AV node blockade induced by adenosine occurred 20 s after injection, and disappeared very quickly. Side-effects were transient and never serious. Therefore, it is thought that adenosine can be proposed safely for the short-term treatment of supraventricular tachycardia. Because of the different mechanisms of action, the specific side-effects observed after ATP administration are unlikely to be encountered.

Airways responsiveness in a population sample of adults and children

Nonspecific bronchial responsiveness was assessed with eucapneic hyperpnea to subfreezing air in a population-based sample of 134 adults and 213 children in East Boston, Massachusetts. Increased responsiveness was considered to be present if the decrease in forced expiratory volume in one second with cold air divided by the initial vital capacity was greater than 9%. Men and women had similar bronchial responsiveness, but children and young adults (24 yr of age and younger) were significantly more likely to be responders than were older subjects (p less than 0.001). Children with a doctor's diagnosis of asthma at any time in the past were twice as likely (42.9%) to be responders as were nonasthmatic children (19%) (p = 0.004). Ninety-two percent (11/12) of currently active asthmatics were responders. However, a large percentage of asymptomatic children had increased levels of bronchial responsiveness (18.9%). This cross-sectional study demonstrates the feasibility of measurement of nonspecific bronchial responsiveness in epidemiologic studies, and its relationship to age and wheeze symptoms in children.