Acceptability of carrier screening for cystic fibrosis during pregnancy in a German population.

A pilot project offering voluntary heterozygote screening for the delta F508 mutation causing cystic fibrosis (CF) to 638 pregnant women attending two antenatal clinics in the eastern part of Berlin was carried out from 1990-1993. Participation was invited using an information leaflet and inclusion in the study was conditional on written informed consent. Of those invited to participate, only one refused to be tested, on the grounds of non-acceptance of prenatal diagnosis. Eighteen pregnant women were identified as carriers of the delta F508 mutation. All of them and their male partners accepted counselling in which the genetics of CF, its prognosis and treatment were explained, with emphasis on the meaning of heterozygosity, the fact that carriers are healthy, and the risk of an affected fetus when only one parent is identified as a heterozygote. All partners agreed to be tested for the delta F508 R553X and G551D mutations and a second counselling session was carried out after this test result was available. No problems were observed during initial testing but, as in other studies, we found considerable anxiety on being given the result in all couples where the woman tested positive; this was reduced substantially by counselling and when the partner tested negative. All probands found to be carriers stated that they found screening acceptable. In contrast to the cautious statement by the German Berufsverband Medizinische Genetik and the hostile reaction from a representative of the CF self-support organisation towards community-based heterozygote screening for CF, this study shows that CF screening is generally acceptable in this German population and that it is actively taken up by most pregnant women when offered.

[Behavior of visual acuity, visual fields and contrast sensitivity in simulated cataract]. / Das Verhalten von Visus, Gesichtsfeld und Kontrastempfindlichkeit unter dem Einfluss einer simulierten Katarakt.

Visual acuity, contrast sensitivity, and visual fields were examined with and without occluders both in a group of healthy subjects and in a group of patients with field defects (mostly caused by glaucoma). The various results were compared with one another as well as with the results obtained from a group of cataract patients examined before and after surgery. The results confirm clinical experience: visual acuity enables some conclusions to be drawn on the degree and progression of opacity of a lens. The changes in contrast sensitivity and in the visual field, however, represent rather the quality of the visual degradation. Contrast sensitivity and diffuse alterations in the visual field have similar progression patterns. The alterations in contrast sensitivity are more pronounced at higher frequency levels. The contrast sensitivity test can be recommended as a simple and complementary functional test, particularly on cataract patients with severe complaints and relatively good visual acuity. The results of occlusive experiments afford some practical conclusions which enhance knowledge and differentiation of visual field changes induced by cataract and glaucoma. These conclusions can provide a basis for further and more detailed investigations.

The shift of Schlemm's canal during the remodelling of the chamber angle in the developing rat eye.

A morphometric analysis of the pre- and postnatal development of the tissue components of the chamber angle was performed in the rat. One eye of each of five weight-matched littermates was evaluated by light microscopy at the following time points: prenatal days 18, 21; day 0 (= day of birth); postnatal days 5, 10, 15, 20, 40, 60. Composite photomicrographs of the entire chamber angle area at a magnification of 5776 X were prepared from each eye under investigation. Developmental stages were analysed by direct measurements between selected anatomical reference points and by computerised calculations that were obtained from geometrical constructions on the photomicrographs. A statistical analysis was performed on the correlation of measurements and calculations with the entire investigated time period. This way, a modification of the allometric growth analysis was developed. Our data indicate that Schlemm's canal undergoes a distinct forward shift from a position next to the peripheral retina towards the chamber angle recess. This forward shift is paralleled by a considerable growth of the ciliary body. In contrast, an arrest of growth of tissues between the end of Descemet's membrane and the anterior end of Schlemm's canal is observed. Thus, with the anterior chamber angle components remaining constant and the posterior ones growing in the meridional diameter, a forward and internal shift of Schlemm's canal results.

The development of the chamber angle in the rat eye. Morphological characteristics of developmental stages.

The pre- and postnatal development of the chamber angle region was studied in the rat. The eyes of five weight-matched littermates were investigated by light- and electron microscopy at each of the following times: prenatal days 14, 17, 18, 21; day of birth; postnatal days 5, 10, 15, 20, 40, 60, 100, 200. Major developmental stages are demonstrated and the morphological characteristics of each stage shown. Developmental periods in the rat are correlated with periods that have previously been outlined in the human (Remé and Lalive 1981). Major periods comprise the following events: I. anlage formation (day 17 prenatal - day postnatal); II. differentiation into definitive structures (days 5-10); III. specialization of definitive structures (days 10-20); IV. final components (days 20-60); V. final molding and rarefaction (days 60-100). Our data indicate that the developing rat eye is a suitable experimental model for studies on the development of the chamber angle. Moreover, this study provides baseline data for a separate investigation on morphogenetic events contributing to the remodeling processes occurring within the vertebrate chamber angle.

The occurrence of cell death during the remodelling of the chamber angle recess in the developing rat eye.

Prenatal and postnatal stages of the developing chamber angle in the rat eye were analysed qualitatively by light and electron microscopy. One eye of each of five weight-matched littermates was investigated at the following time points: prenatal days 14, 17, 18 and 21; day 0 = day of birth; postnatal days 5, 10, 15, 20, 40, 60, 100 and 200. From postnatal days 5 to 60, conspicuous amounts of necrotic cells were observed within the chamber angle area. At birth and at postnatal day 200, only a few scattered necroses were observed. Necrotic cells were found within the trabecular area, the region of Fontana's spaces and beams and the peripheral iris, the iris root, the ciliary body and the adjoining choroid. Large macrophages containing lysosomal dense bodies were found within the previously described areas and were frequently in close contact with necrotic cells. It is concluded that cell death within the developing chamber angle of the rat may represent an important event that may contribute to two morphogenetic effects: (1) the opening of large spaces of Fontana and (2) space formation within the trabecular area and uveoscleral outflow routes.