Serum Clara cell protein (CC16) in healthy young smokers

The CC16 microprotein is the main secretory product of Clara cells, which are epithelial cells lining lung airways. In crossing through the bronchoalveolar/blood barrier, CC16 diffuses passively into plasma. Serum CC16 (sCC16) has recently been proposed as a biomarker for detecting Clara cell impairments. The aim of this study was to assess if sCC16 concentrations are reduced in a group of healthy young smokers. A group of 118 healthy young males volunteered to take part in the study. Each subject answered a questionnaire, and provided blood and urine samples. Serum CC16, urinary cotinine and creatinine were measured. Median serum CC16 concentrations were lower in smokers than in non-smokers (11.3 mug l^-1 vs 14.6 mug l^-1; p = 0.005; N = 89 and 29, respectively) but did not correlate with either the daily or the life-time cigarette consumption, or with urinary cotinine concentrations. sCC16 did not correlate with age or body mass index in the whole study population or in the groups of smokers and non-smokers. These results suggest the reduction in sCC16 concentrations in a group of healthy young smokers may be an early effect of cigarette smoking.     

Interactions Between Physical and Biological Constraints in the Structure of the Inflorescences of the Araceae

A study of the inflorescences ofMonsteraandAnthuriumwas usedto establish a relationship between biological and physicalconstraints for the structure of plant organs. The physicalconstraint between flowers in the compact inflorescences ofAnthuriumandMonsteraisexpressed by Aboav-Weaire's law. The application of this lawto inflorescences indicates a linear relationship between thenumber of sides of a flower and the number of sides of neighbouringflowers. However, the slope of this straight line is significantlyhigher forAnthuriumandMonsterathan that expected in theory.This deviation from the law is attributable to a biologicalcause that can be estimated using Aboav-Weaire's law. Actingalone, the biological constraint tends to produce four-sidedflowers. The equilibrium between biological and physical constraintsreduces the number of sides per flower from six (theoreticalvalue) to 5.9 (inAnthurium) or 5.8 (inMonstera) with a varianceof the measures less than that expected in theory. Furthermore,when flower density in an inflorescence increases (towards themiddle of the inflorescence inMonsteraand towards the lowersection forAnthurium) the number of sides approaches six (i.e.the physical constraint dominates). When flower density decreases(towards the top of the inflorescence) the number of sides approaches5.5 (i.e. the biological constraint dominates). The geometryof the inflorescences ofAnthuriumandMonsterais the result ofthe joint action of biological and physical constraints.Copyright1998 Annals of Botany Company Monstera,Anthurium, Araceae, Aboav-Weaire, inflorescence, constraint, flower.