Genetic susceptibility to advanced retinopathy of prematurity (ROP)

Retinopathy of prematurity (ROP) is a vascular vitreoretinopathy that affects infants with short gestational age and low birth-weight. The condition is a multifactorial disease and is clinically similar to familial exudative vitreoretinopathy (FEVR), which is a bilateral hereditary eye disorder affecting full-term infants. Both of them are characterized by the abnormal vessel growth in the vitreous that can lead to vitreoretinal traction, retinal detachment and other complications resulting in blindness. Despite the recent advances in diagnosis and treatment, ROP remains a major cause of childhood blindness in developed countries. The etiology of pathogenesis of advanced ROP is currently unknown. In the past, many causative factors such as length of time exposed to supplemental oxygen, excessive ambient light exposure and hypoxia have been suggested but evidence for these as independent risk factors in recent years is not compelling. It is not clear why ROP in a subset of infants with low birth-weight progresses to a severe stage (retinal detachment) despite timely intervention whereas in other infants with similar clinical characteristics ROP regresses spontaneously. Recent research with candidate gene approach, higher concordance rate in monozygotic twins and other clinical and experimental animal studies, suggest a strong genetic predisposition to ROP besides environmental factors such as prematurity. Three genes, which are involved in the Wnt signaling pathway, are mutated in both FEVR and in a small percentage of ROP disorder. However, none of the genetic factors identified thus far in ROP, account for a substantial number of patient population. Future studies involving genomics, bioinformatics and proteomics may provide a better understanding of the pathophysiology and management of ROP

Izloženost štakora niskim razinama olova tijekom fetalnog i ranoga postnatalnog razvoja šteti učenju pasivnim izbjegavanjem kazne kasnije u odrasloj dobi

This follow-up study investigated the effects of low-level lead exposure during prenatal and early postnatal period on learning and memory in rats immediately after exposure has ceased at weaning and later in their adulthood. Male Wistar-derived rats were exposed to lead (as 0.2 % lead acetate solution) through their mothers during pregnancy and lactation until they were weaned. Mothers of control rats were given tap water during pregnancy and lactation. All pups were weaned on tap water at 21 days of age and were followed up until 120 days old. Low-level lead exposure did not affect their body weight at any time during the experiment. Blood lead in the exposed rats was significantly higher on postnatal day 22 and dropped to control values by day 120. Passive avoidance test showed impaired memory retention in the exposed rats on postnatal days 25 and 120. This suggests that exposure to low-lead levels during foetal and early postnatal development of brain tissue can cause memory impairment that lasts into adulthood.Cilj je ovoga prospektivnog istraživanja bio utvrditi kako izloženost niskim razinama olova tijekom gestacije i ranoga postnatalnog razvoja utječe na učenje i pamćenje u štakora odmah nakon prestanka izloženosti (odbijanjem od sise) te kasnije u odrasloj dobi. Mužjaci štakora izloženi su olovu u obliku 0,2 %-tne otopine olovova acetata preko majke tijekom gestacije te za cijeloga trajanja laktacije sve do odbijanja od sise. Sve to vrijeme majke kontrolnih štakora dobivale su vodu iz pipe. Svi su štakorčići odbijeni od sise 21 dan nakon okota i otada piju vodu iz pipe. Praćeni su do 120. dana života. Izloženost niskim razinama olova nije dovela do razlika u tjelesnoj težini između izloženih i kontrolnih štakorčića. Razine olova u krvi bile su značajno više u izloženih štakora 22 dana od okota, da bi do 120. dana pale na razinu u kontrolnih štakora. Test pasivnoga izbjegavanja pokazao je oštećenje pamćenja u izloženih štakora 25. i 120. dana nakon okota. To potvrđuje da izloženost niskim razinama olova tijekom fetalnoga i ranoga postnatalnog razvoja moždanog tkiva može dovesti to oštećenja u pamćenju koje traje sve do odrasle dobi

Genetic Susceptibility to Normal Tension Glaucoma (NTG)

Aims: The Purpose of this short article is to summarize the recent developments in the genetics of normal tension glaucoma (NTG). Background: Glaucoma is one of the leading causes of irreversible blindness. Primary open-angle glaucoma (POAG) is the most common type of glaucoma in most populations and is frequently associated with elevated intraocular pressure (IOP). However, patients with POAG can also have IOP within the normal range and they are classified as having normal tension glaucoma (NTG) – most likely an independent entity. In NTG, the optic nerve head is just susceptible to normal IOP. Therefore, factors other than elevated IOP are likely to play a role in the pathogenesis of glaucoma. Although factors such as myopia, older age, vasospasm, ischemia and vascular insufficiency are indicated to be associated with the development of NTG, substantial percentage of NTG patients (21%) have a family history of glaucoma suggesting that these patients may have a genetic predisposition for developing NTG. Methodology: Using the keywords or phrases such as glaucoma, genetics, normal tension glaucoma, open-angle glaucoma and retinal ganglion cell, the literature search was carried out. Results: NTG is a genetically complex disorder and many genes have been reported to be associated with the development of glaucoma. However, none of them account for a substantial portion of patient population. A complex glaucoma pathogenesis may include interplay among several factors such as genetic, epigenetic and environmental factors. Therefore, an understanding of IOP independent mechanisms of development of NTG is important. Conclusion: NTG is relatively a less explored avenue of research. There has been paucity of research into the genetic basis of NTG

Autosomal Recessive Familial Exudative Vitreoretinopathy Is Associated with Mutations in LRP5

Familial exudative vitreoretinopathy (FEVR) is a hereditary eye disorder that affects both the retina and vitreous body. Autosomal recessive FEVR was diagnosed in multiple individuals from three consanguineous families of European descent. A candidate-locus–directed genome scan shows linkage to the region on chromosome 11q flanked by markers D11S905 and D11S1314. The maximum LOD score of 3.6 at θ=0 is obtained with marker D11S987. Haplotype analysis confirms that the critical region is the 22-cM (311-Mb) interval flanked by markers D11S905 and D11S1314. This region contains LRP5 but not FZD4; mutations in both of these genes cause autosomal dominant FEVR. Sequencing of LRP5 shows, in all three families, homozygous mutations R570Q, R752G, and E1367K. This suggests that mutations in this gene can cause autosomal recessive as well as autosomal dominant FEVR

Intraoperative spectroscopic evaluation of sentinel lymph nodes in breast cancer surgery

Background and objectives: Sentinel lymph node (SLN) biopsy is a standard procedure for patients with breast cancer and normal axilla on imaging. Positive SLNs on histological examination can lead to a subsequent surgery for axillary lymph node clearance (ALNC). Here we report a non-destructive technique based on autofluorescence (AF) imaging and Raman spectroscopy for intra-operative assessment of SLNs excised in breast cancer surgery.Methods: A microscope integrating AF imaging and Raman spectroscopy modules was built to allow scanning of lymph node biopsy samples. During AF-Raman measurements, AF imaging determined optimal sampling locations for Raman spectroscopy measurements. After optimisation of the AF image analysis and training of classification models based on data from 85 samples, the AF-Raman technique was tested on an independent set of 81 lymph nodes comprised of 58 fixed and 23 fresh specimens. The sensitivity and specificity of AF-Raman were calculated using post-operative histology as a standard of reference.Results: The independent set contained 66 negative lymph nodes and 15 positive lymph nodes according to the reference standard, collected from 78 patients recruited randomly. For this set of specimens, the area under the receiver operating characteristic (ROC) curve for the AF-Raman technique was 0.93 [0.83-0.98]. AF-Raman was then operated in a regime that maximised detection specificity, producing a 94% detection accuracy: 80% sensitivity and 97% specificity. The main confounders for SLN metastasis were areas rich in histiocytes clusters, for which only few Raman spectra had been included in the training dataset.Discussion: This preliminary study indicates that with further development and extension of the training dataset by inclusion of additional Raman spectra of histiocytes clusters and capsule, the AF-Raman may become a promising technique for intra-operative assessment of SLNs. Intra-operative detection of positive biopsies could avoid second surgery for axillary clearance