Kristina Tornqvist

Incidence of and risk factors for neonatal morbidity after active perinatal care : extremely preterm infants study in Sweden (EXPRESS)

Aims:  The aim of this study was to determine the incidence of neonatal morbidity in extremely preterm infants and to identify associated risk factors.

Somatostatin and VIP neurons in the retina of different species

SummaryNeurons displaying somatostatin or vasoactive intestinal polypeptide (VIP) immunoreactivity were detected among the amacrine cells in the retina of baboon, cynomolgus monkey, squirrel monkey, cow, pig, cat, rabbit, guinea-pig, rat, mouse, frog and goldfish. Generally, immunoreactive cell bodies were located in the inner nuclear layer with processes ramifying in three more or less well-defined sublayers in the inner plexiform layer. The density of the sublayers and their location varied with the peptide and species investigated. In most cases there was a sublayer in the outermost part (Ramon y Cajals sublamina 1) of the inner plexiform layer and this sublayer was usually the best developed. In some species a few somatostatin fibres were also detected in the outer plexiform layer, suggesting that some interplexiform cells contain somatostatin. In the baboon VIP was found exclusively in interstitial amacrine cells which have their cell bodies and processes entirely within the inner plexiform layer.

VIP (vasoactive intestinal polypeptide)-immunoreactive neurons in the retina of the rat.

SummaryImmunoreactive vasoactive intestinal polypeptide (VIP) was detected in a population of amacrine cells in the retina of the rat. Processes of these cells reach both the inner and outer half of the inner plexiform layer where they form sublayers. The VIP neurons are different from previously known amacrine cell types.

Peptide-containing neurons in the chicken retina

Four populations of cells showing immunoreactivity towards glucagon, somatostatin, enkephalin and neurotensin respectively were detected among the amacrine cells in the chicken retina. Processes of these different cell types formed sublayers in different laminae of the inner plexiform layer. The distribution of cell bodies and processes varied with the type of immunoreactive neuron investigated.

Intrafamilial variation of the phenotype in Bardet-Biedl syndrome

AIMS To describe the variation of the phenotype within families with several individuals with Bardet–Biedl syndrome. METHODS The phenotypes of affected siblings in 11 Scandinavian families were compared with two or more members who had at least three of the features: retinal dystrophy, polydactyly, obesity, hypogenitalism, and mental retardation. Individuals without retinal dystrophy were excluded. RESULTS Intrafamilial variation of expressivity of the features obesity, polydactyly, abnormal radiograms of the extremities, hypogenitalism, short stature, paraplegia, and dental abnormalities was found. The retinal dystrophy varied with respect to both the onset of symptoms and the course of the disease. The morphology of the fundus, however, was consistent within the families. The disorder showed statistically significant genetic linkage to the BBS4 locus on chromosome 15 in the affected siblings in two of the families, but the clinical features in these patients did not differ from the other cases of Bardet–Biedl syndrome. CONCLUSION Comparison of siblings with the Bardet–Biedl syndrome showed variation of the typical features. In addition, the course of retinal dystrophy varied. No distinctive clinical features were found to separate the BBS4 phenotype from the remaining patients.

5-Hydroxytryptamine in the retina of some mammals.

A set of indoleamine accumulating neurons has been described in the retina of several species. Their transmitter is unknown though 5-hydroxytryptamine has been suggested. We have studied the 5-hydroxytryptamine concentration in the retina of cows, pigs, guinea-pigs and also of rabbits in which the blood had been washed out. It was found to be 26·2 ng/g ( s.e.m. =7·17) in cow retina, 5·9 ( s.e.m. =0·83) in pig retina and 6·03 ng/g ( s.e.m. =2·61) in guinea-pig retina. Concentrations in this range could well be due to blood platelet 5-hydroxytryptamine and this was corroborated by the about six-fold fall from the normal concentration to 3·8 ng/g ( s.e.m. =0·9) which occurred when rabbit retinas were perfused to remove the blood. The possible presence of indoleamine accumulating neurons in some mammals (cow and pig) was also investigated by means of fluorescence microscopy. No indoleamine accumulating neurons could be found with this technique. Nevertheless, autoradiography has shown that there are indoleamine accumulating neurons in the cow and pig retina, and we suggest that these neurons have the ability to modify the indoleamines they accumulate into substances related to 5-hydroxytryptamine but unable to form fluorophores with formaldehyde in tissues.

The epidemiology of anophthalmia and microphthalmia in Sweden.

Infants with a clinical diagnosis of anophthalmia or microphthalmia were identified from four health registers in Sweden, covering different parts of the period 1965–2001. During the observation period, the rate of anophthalmia decreased from the early 1970s from 0.4 to 0.2 per 10,000 births. The registered rate of microphthalmia increased markedly during the observation period to reach a maximum in 1987 of about 1.5 per 10,000. About 10% of the 432 identified children had a chromosome anomaly. There was no geographical variation in prevalence and infants born in urban or rural districts had, if anything, a lower risk than infants born in cities (0.93 and 1.13 per 10,000, respectively). Non-eye malformations were more common at anophthalmia (63%) than at microphthalmia (30%). Sex ratio was normal and no statistically significant variation between sub-groups (anophthalmia, microphthalmia, isolated, associated with non-eye malformations) could be demonstrated. There was a marked risk increase with maternal age but no certain parity effect, no effect of maternal education, but a possible association with subfertility. Maternal smoking in early pregnancy seemed to increase the risk for anophthalmia or microphthalmia in the absence of a coloboma.

Neuropeptide Y (NPY) immunoreactive neurons in the retina of different species

SummaryNeurons displaying Neuropeptide Y (NPY) immunoreactivity were found among amacrine cells in the retina of baboon, pig, cat, pigeon, chicken, frog, trout, carp and goldfish. The immunoreactive cell bodies were located in the middle and the innermost cell rows of the inner nuclear layer with processes forming one, two or three more or less well-defined sublayers in the inner plexiform layer. The location and the density of the sublayers varied with the species investigated. In the frog retina, bipolar-like cell bodies were found in the middle of the inner nuclear layer as well as sparsely occurring ovoid cell bodies in the ganglion cell layer. Like the amacrine cells, these cells emitted processes ramifying in three sublayers in the inner plexiform layer.

Substance P-immunoreactive nerve fibres in the anterior segment of the rabbit eye

SummarySubstance P-immunoreactive nerve terminals were found in several locations in the anterior segment of the rabbit eye. In the iris they occurred in the sphincter muscle and were randomly distributed in the iris stroma with some fibres running close to the dilator muscle. In the ciliary body these immunoreactive elements were few and occurred within bundles of nerve fibres, while in the ciliary processes they were more numerous with a predominantly subepithelial location. Blood vessels in the anterior uvea were often surrounded by substance P-immunoreactive fibres. No substance P-fibres were found in the cornea, while the sclera contained very few such elements.Using conventional in vitro techniques it was found that the sphincter pupillae muscle of the iris responded to electrical stimulation with a contraction that was resistant to cholinergic and adrenergic blockade, but was inhibited by the neuronal blocker tetrodotoxin. This indicates the existence of a non-cholinergic, non-adrenergic neuronal mediator of the contractile response. Exogenously applied substance P produced a long-lasting contraction of the spincter muscle, an observation compatible with the view that substance P is the noncholinergic, non-adrenergic neurotransmitter involved.

Epidemiology of aniridia in Sweden and Norway

Purpose:  To investigate the epidemiology of aniridia in the populations of Sweden and Norway.