Rationale: Severe a 1 -antitrypsin deficiency (typically PiZZ homozygosity) is associated with a significantly increased risk of airflow obstruction and emphysema but the risk of chronic obstructive pulmonary disease (COPD) in PiMZ heterozygotes remains uncertain.Objectives: This was a family-based study to determine the risk of COPD in PiMZ individuals. (% predicted) (63.84 [38.45-84.35] vs. 72.8 [55.5-97.7]; P = 0.0013) compared with PiMM individuals. This effect was abrogated in never-smoking and accentuated in ever-smoking PiMZ individuals. PiMZ heterozygosity was associated with an adjusted odds ratio for COPD of 5.18 (95% confidence interval, 1.27-21.15; P = 0.02) and this was higher (odds ratio, 10.65; 95% confidence interval, 2.17-52.29; P = 0.004) in eversmoking individuals.Conclusions: These results indicate that PiMZ heterozygotes have significantly more airflow obstruction and COPD than PiMM individuals and cigarette smoke exposure exerts a significant modifier effect.
The incidence of SCD in the young in Ireland was 4.96 (95% CI 3.06, 6.4) for males and 1.3 (95% CI 0.62, 2.56) for females per 100 000 person-years. Sudden arrhythmic death syndrome was the commonest cause of SCD in the young, and the incidence of SADS was more than five times that in official reports of the Irish CSO.
Rods, double cones which comprise a principal and an accessory cone, and two types of single cones occur in the chick retina. The rod is narrow and contains a paraboloid, a basal nucleus and a small synaptic body with long synaptic lamellae. The principal cone has a pale-staining oil droplet and is aligned against a n accessory cone, which has a paraboloid, no oil droplet, but a small granular vesicle instead. The synaptic body of the principal cone is large and partly surrounds that of its associated accessory cone. The synaptic body of the accessory cone has a long process extending into the outer plexiform layer. Single cone type I has a dark oil droplet and the mitochondria in the ellipsoid are dense with cristae. Single cone type I1 has a lighterstaining oil droplet and fewer cristae. The synaptic bodies of both types of single cone lie vitreal to those of rods and double cones. Fibres connect the synaptic body to the nuclear region in single cones and accessory cones, but not in rods and principal cones. Another type of synaptic body, which is not that of a receptor, occurs in the outer plexiform layer. Groups of small vesicles, like those in the synaptic body, occur near the base of the inner segments; synaptic vesicles may originate here. Muller cells separate each receptor, except the members of a double cone, at the outer limiting membrane and may position the receptors in relation to the pigment epithelium to allow a radial orientation of the inner and outer segments.The visual receptors in many vertebrate retinas show a remarkable diversity of form (Walls, '42). In the chick retina, rods, double cones each comprising a principal and an accessory cone, and single cones with either a red or yellow oil droplet were recognised long ago (Schultze, 1867). An electron microscope study of these receptors in the chick has not been reported, though in some general descriptions of the ultrastructure of vertebrate retinal cells (Villegas, '60; Pedler, '65), the chicken retina was amongst the material examined. The present report is a description of the fine structure of receptor types in the chick retina. The description is based on radial sections of the retina in which a single receptor could be traced along its entire length from outer segment to synaptic body. It has thus been possible to describe the synaptic body of each type of receptor.The general ultrastructural features of vertebrate retinal receptors are well known and have been reviewed by Cohen ('63b). Ultrastructural studies of avian retinal receptors include those on the pigeon (Cohen, '63a) and weaver-finch (Yasuzumi et al., '58). There have been few classifications of the types of retinal receptors in one species of vertebrate, such as that carried out by Nilsson ('64a) on the leopard frog. Our aim is to present such an account for the chick. It forms a basis for future descriptions of the connexions between receptors and cells in the bipolar layer and for an understanding of the role of different receptors in visual function.MATERIAL AND...
The mean percentages of receptors in the central retina were 14% rods, 32% double cones and 54% single cones. The mean percentages in the periphery were 33% rods, 30% double cones and 37% single cones. Single cones were classified into type I, type I1 and type I11 and the ratio of these types was about 5:2:1, respectively, in both central and peripheral retina. A statistical analysis showed that each type of receptor was evenly spaced i n the receptor mosaic, but single cone type I tended to occur in pairs. The types of receptor were arranged in a pattern which was in the form of a hexagonal lattice. The pattern in the mosaic is regarded as the outcome of an evenly spaced distribution of the types of receptor. Perhaps pattern in the receptor mosaics of other vertebrate retinae should be interpreted as evenly spaced distributions of the types of receptor present. A method for detectinz pattern in receptor mosaics, in which pattern is obscure, is described. A scheme accounting for the formation of the pattern in the chick retina during development is proposed.
The expression of Hox11/13 and Hox5 orthologues in the adult echinoid rudiment in the vestibula larva of Holopneustes purpurescens is described from whole mounts and sections of whole mounts after mRNA in situ hybridization. The Hox5 orthologue is HpHox5, which was isolated here. The expression of HpHox11/13 in the epithelium of the vestibule is aboral to the expression of HpHox5. HpHox5 is expressed in the epithelium of the vestibule floor where the secondary podia develop. The expression of HpHox11/13 and HpHox5 contrasts with the expression of an Otx orthologue, HprOtx, in the circum-oral nerve ring, the radial nerves and the neuroepithelium around the bases of the primary podia. From the expression patterns, we conclude that the two Hox genes are involved in the growth of a metameric series of secondary podia from a growth zone aboral to each primary podium, with the older podia nearer the circum-oral nerve ring. With respect to echinoderm body-plan polarities, we conclude that the growth zone is posterior relative to the anterior circum-oral nerve ring. The metamerism generated in this echinoderm from a posterior growth zone thus might not be generated differently from the way it is generated in bilateral animals.
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