Ocular ischaemia: signs, symptoms, and clinical considerations for primary eye care practitioners.

Ischaemic stroke is a major disease burden as well as a leading cause of death. Early signs of ischaemic stroke can manifest in the eye, placing primary eyecare practitioners in an important position to identify patients at risk of ischaemic stroke and initiate suitable referral pathways. The vascular supply to the brain is reviewed with reference to vision including the various retinal signs and ocular symptoms associated with transient ischaemic attacks and ischaemic stroke. Using a range of clinical cases, the diverse clinical presentations of retinal embolic events, as well as other forms of vascular occlusion, are highlighted and the underlying pathophysiology is discussed. A succinct scheme for the assessment and management of ischaemic events for primary eye care practitioners is provided.

Deficiency in endothelin receptor B reduces proliferation of neuronal progenitors and increases apoptosis in postnatal rat cerebellum.

Endothelins regulate cellular functions in the mammalian brain through the endothelin receptors A and B (EDNRA and EDNRB). In this study, we investigated the role of EDNRB on cell proliferation in the cerebellum by using the spotting lethal (sl) rat, which carries a naturally occurring deletion in the EDNRB gene. Proliferating cells in the three genotypes, wild-type (+/+), heterozygous (+/sl) and homozygous mutant (sl/sl) rats were labelled by intraperitoneal injection of 5-bromo-2'-deoxyuridine (BrdU) at postnatal day 2. The density of BrdU-positive cells (per mm(2)) in the external germinal layer of sl/sl rats (Mean +/- SEM, 977 +/- 388) was significantly reduced compared to +/+ (4915 +/- 631) and +/sl (2304 +/- 557) rats. Subsequently, we examined the effects of EDNRB mutation on neural apoptosis by terminal deoxynucleotidyltransferase-mediated dUTP nick end-labelling assay. This showed that the density of apoptotic cells in the cerebella of sl/sl rats (9.3 +/- 0.5/mm(2)) was significantly more increased than +/+ rats (4 +/- 0.7). The expression of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) were measured with standard ELISA, but were unchanged in all genotypes. These results suggest that ENDRB mediates neural proliferation and have anti-apoptotic effects in the cerebellum of the postnatal rat, and that these effects are independent of changes in the expression of BDNF and GDNF. Our findings will lead to better understanding of the morphological changes in the cerebellum of Hirschsprung's disease patients with congenital EDNRB mutation.