Temporal trends of malondialdehyde in stored human plasma.

Malondialdehyde (MDA) is widely used as oxidative stress biomarker in biomedical research. Plasma is stored in deep freezers generally till analysis. Effect of such storage on MDA values, which may be variable and prolong, was incidentally observed in the ongoing study which is to estimate oxidative stress with oral iron. Plasma from blood samples of pregnant women (20-30 years age) in third trimester of singleton pregnancy (n = 139), consuming oral iron tablets was stored at -20 °C with intention of MDA estimation, as soon as possible. However logistic problems led this storage for prolonged and variable period (1-708 days). When values of MDA estimated using "Ohkawa" 79 method and readings were plotted against time to check the temporal effect, it showed a hyperbolic curve. Standard deviation (SD) was lowest when samples were tested within 3 weeks time. The samples analyzed within 3 weeks had mean ± SD value of 31.59 ± 26.11 µmol/L, while 123.7 ± 93.97 and 366.5 ± 189.8 µmol/L for samples stored for 1-3 and 4 months to 1 year respectively. Mean ± SD were 539.9 ± 196.8 in the samples store for more than a year. Rate of change in values was also lowest (0.0433 µmol/L/day) in the samples tested within first 3 weeks, which rose to 1.2 µmol/L/day during 3 month's storage. This rate peaked at storage of 120 days (1.87 µmol/L/day) and fell to 0.502 µmol/L/day in the second year of storage. It is concluded that at -20 °C, only 3 weeks of storage time should be considered valid for fairly acceptable stability in MDA values.

Integrated use of phosphorus, farmyard manure and biofertilizer improves the yield and phosphorus uptake of black gram in silt loam soil.

An experiment on the use of farmyard manure and biofertilizer along with application of chemical phosphorus was conducted to assess the impact of differential doses of phosphorus, farmyard manure and consortium biofertilizer application on the development, yield and phosphorus uptake during the year 2018 and 2019. The impact of different treatments was recorded on the plant height, dry matter partition, yield and yield attributes, phosphorus uptake and soil phosphorus availability using standard methods. The data revealed significant improvement in yield, yield attributes, phosphorus uptake and soil phosphorus availability. The integration of farmyard manure and biofertilizer with 60 kg ha-1 SSP (single superphosphate) has improved the black gram yield by 7.4% and 3.28% respectively over the use of 60 SSP alone. The phosphorus uptake in black gram with application of Farm yard manure and biofertilizer along with 60 kg ha-1 SSP has improved the uptake by 7.18% and 2.51% respectively over the use of 60 kg ha-1 SSP alone. The results highlight the need of integrated application of farm yard manure, biofertilizer for sustainable production of black gram in the region.

Multi-system neurological disease is common in patients with OPA1 mutations.

Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal 'dominant optic atrophy plus' variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44-6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08-4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment.

Molecular marker assisted broadening of the Central European heterotic groups in rye with Eastern European germplasm.

Broadening the genetic base of heterotic pools is a key to ensure continued genetic gains in hybrid breeding and extend hybrid cultivation to new areas. In the present study, two Central European heterotic pools (Carsten and Petkus) and five Eastern European open-pollinated varieties (OPVs, Pop-1 to Pop-5) were studied with the objectives to (1) investigate the genetic diversity in OPVs and the heterotic pools using molecular and field data, (2) evaluate the molecular diversity among OPVs, (3) examine the combining ability for grain yield of the OPVs when crossed with testers in field trials, and (4) develop a strategy for targeted introgression of OPV germplasm into the heterotic pools. In total, 610 S(0) plants, 347 from OPVs and 263 from heterotic pools, were developed. Clones of the S(0) plants of OPVs were crossed with two testers belonging to each heterotic pool, while clones of heterotic pools were crossed with only the opposite tester. Testcrosses were evaluated for grain yield in multi-location trials. In addition, 589 S(0) plants were fingerprinted with 30 SSR markers. The data revealed that the Carsten pool has a narrow genetic base and should be the primary target for broadening the established heterotic pattern. Mean and genetic variance suggested that Pop-2 and Pop-4 are good candidates for introgression in Petkus pool and Pop-5 in Carsten pool. Nevertheless, introgression of Pop-5 in Carsten could reduce the genetic diversity between heterotic pools. Therefore, we suggest that either selected plants of Pop-5 should be introgressed or more Eastern European germplasm should be fingerprinted and field evaluated to identify promising germplasm for broadening the established heterotic pattern.

Republished review. [corrected] Late-onset retinal macular degeneration: clinical insights into an inherited retinal degeneration.

AIM: This study describes, in detail, the phenotype of late-onset retinal macular degeneration (L-ORMD) an inherited condition affecting both the retina and anterior segment. A staging based on clinical characteristics is proposed, and the relevance of this condition to current understanding of age-related macular degeneration is discussed. METHODS: A systematic review of the literature regarding this condition supports a detailed description of the natural history. Clinical experiences in identifying, monitoring and managing patients are also presented. RESULTS: L-ORMD is a rare fully penetrant autosomal dominant condition resulting from a mutation in the C1QTNF5 gene on chromosome 11. Affected individuals develop bilateral loss of vision, dark-adaptation abnormalities, fundus drusen-like yellow spots, midperipheral pigmentation, choroidal neovascularisation, chorioretinal atrophy and long anteriorly inserted lens zonules. Patients may benefit from treatment with high-dose vitamin A. CONCLUSIONS: Raised awareness of L-ORMD should lead to earlier diagnosis and improved care for patients. New antivascular endothelial growth factor treatment may provide a new possibility for management. A deeper insight into molecular and genetic mechanisms of L-ORMD may suggest avenues to explore new treatments of this disorder.

Importance of side marking in ophthalmic surgery.

BACKGROUND: In 2003 the National Patient Safety Agency (NPSA) advised side marking for avoiding errors and reducing incorrect side surgery. This survey aimed to ascertain whether or not, these 'best practice' guidelines are currently being implemented by ophthalmic surgeons in Scotland and, if not, the reasons for this, and also to ascertain surgeons' attitudes towards marking. METHODS: Semi-structured interviews with ophthalmic surgeons throughout Scotland, either face to face or by telephone, on their current practices and attitudes relating to preventing wrong side surgery. RESULTS: Non-compliance with side marking was described by 48% of the surgeons, which includes both consultants and specialist registrars. This survey reveals incomplete implementation of this policy in ophthalmic surgery for a number of reasons. The most common was bypassing the established multi-step process of checks, which risks an increased likelihood of surgical errors. CONCLUSION: Guidelines are not consistently being implemented in their entirety by eye surgeons in Scotland. In order to improve compliance and improve patient safety, we suggest a risk-stratified approach in side marking based on individual patient factors that may encourage wider acceptance, without compromising patient safety.

A Novel Mutation in the Adult-Onset Alexander's Disease GFAP Gene.

The case describes a 25-year-old Caucasian female diagnosed with Alexander's disease (AxD) as an outpatient after extensive inpatient workup. Her presenting complaints included incontinence, clumsiness, seizures, dysphagia, and dysarthria. She was also found to have pancytopenia and dysautonomia. A full neurologic and hematologic workup yielded very little results, until a thorough literature search of her presenting complaints and radiologic findings pointed to adult-onset Alexander's Disease. Alexander's disease is a rare genetic leukodystrophy with a broad variety of presentations. Despite its infrequency in adults and the difficulty in diagnosis, the prevalence of AxD has been increasing due to ease of genetic analysis and identification of key clinical and radiological findings. This case illustrates the necessity of vigilance and persistence in the face of unusual patient presentations; occasionally, the sound of hoofbeats is zebras.

Exploring factors predicting changes in patients' expectations and psychosocial issues during the course of treatment with intravitreal injections for wet age-related macular degeneration.

PurposePatients with wet age-related macular degeneration (AMD) often require long courses of treatment. We investigate the psychosocial issues that could hinder compliance, including patient expectations of treatment. The aims of this study were to explore the factors related to changes in patient expectations, pain, and anxiety during treatment.Patients and methodsA structured interview was carried out among 50 patients selected from the list attending the AMD unit at the Princess Alexandra Eye Pavilion (PAEP). The interview was based on a questionnaire. Additionally, a visual analogue scale was created as a tool for measuring patient expectations, pain, and anxiety. Data were analysed using multinomial regression analysis.ResultsThere were significantly more patients who had a fall in expectations (P<0.05) during the course of treatment. A fall in expectations was found to be predicted by higher starting expectations (P=0.00001), greater decline in visual acuity (P=0.008), and perceived deterioration of vision after starting treatment (P=0.013). Of the patients, 32% planned to stop attending for further injections. Planning to stop attending was correlated with worse final visual acuity (P=0.026, 95% CI). Pain and anxiety with intravitreal therapy (IVT) was significantly reduced when patients were accompanied to the clinic by a friend or relative (P<0.01) using Pearson's correlation (r=0.597).ConclusionPatients require appropriate counselling at the start of a course of treatment to align expectations with perceived treatment outcomes in order to improve adherence. Additionally, a large minority of patients would consider stopping treatment. Patients' expectations should be assessed at relevant time points along a course of treatment.

Congenital corneal anesthesia.

Congenital corneal anesthesia is a rare clinical entity that poses a diagnostic dilemma, particularly in the pediatric age group. The sensory deficit may be confined to the cornea, or extend to other divisions of the trigeminal nerve. The sensory deficit may occur as an isolated abnormality, as part of a complex neurological syndrome, or it may occur in association with multiple somatic abnormalities and congenital insensitivity to pain. This condition usually presents between the ages of 8 to 12 months. Poor vision, photophobia, conjunctival injection, and corneal ulceration in the absence of pain and distress in a child should alert the clinician to the possibility of anesthetic cornea. In the early stages of presentation, punctuate keratopathy is the main feature, which may progress to non-healing persistent corneal epithelial defects. This stage may progress to acute corneal lysis and perforation. In most patients, conservative approaches such as copious lubrication, prevention of self-harm and cautious use of bandage contact lenses are effective in preventing progressive corneal damage. Tarsorrhapy is effective in promoting epithelial healing and permanent lateral tarsorraphy may prevent further development of epithelial defects. Amniotic membrane graft may be considered in order to improve epithelial healing. Corneal grafts carry a poor prognosis. Accurate initial diagnosis, evaluation, and proper management are paramount to prevent visual loss due to long-term complications of corneal anesthesia. This review of the literature outlines the problems and approaches in diagnosis, evaluation, and management of this rare condition.

Quality of life and relative importance: a comparison of time trade-off and conjoint analysis methods in patients with age-related macular degeneration.

AIM: To investigate the relative priorities in quality of life (QoL) in patients with age-related macular degeneration (AMD). METHODS: Measures of visual function, QoL and utility associated with visual loss were obtained from 122 patients with AMD classified according to macular morphology. The two methods of utility assessment were time trade-off (TTO) and conjoint analysis (CA), which have been recommended by the UK's National Institute of Clinical Excellence as techniques for the assessment of healthcare priorities. RESULTS: Results show that the two methods for assessing utility are poorly related: TTO relates moderately to visual function and disease severity but CA does not. CA identified two different subgroups of patients: one with outdoor mobility and the other with reading as their main priority. CONCLUSION: Further work is needed and caution required in interpreting data obtained using these methodologies for determining their relative importance in vision-related QoL studies.

Temporal artery biopsies in south-east Scotland: a five year review.

Temporal artery biopsy is the gold standard investigation for the diagnosis of giant cell arteritis. The aim of this retrospective study was to investigate the use of temporal artery biopsy in diagnosing giant cell arteritis in south-east Scotland over a five-year period. We aimed to quantify success rates, and predictive factors for a positive biopsy, as well as compare the different specialities performing the biopsies. The data should enable the development of better criteria for referral for investigation of giant cell arteritis. Methods Patients were identified using a database of temporal artery biopsies generated by the pathology department in NHS Lothian (south east Scotland), for all biopsies examined between January 2010 and December 2015. An electronic patient record was used to retrospectively examine the records of patients in the database. Results A total of 715 biopsies were included in the study, of which 250 (35.0%) showed features of giant cell arteritis. The main predictors for a positive biopsy were age at biopsy, specialty performing biopsy, erythrocyte sedimentation rate, jaw claudication/pain, and ophthalmic symptoms. The most important predictor of a positive biopsy was erythrocyte sedimentation rate. The length of biopsy was not found to be a predictor of positive biopsy; however, diameter of biopsy was predictive. Conclusions We have shown that many temporal artery biopsies are negative, and finding ways to reduce the number of patients unnecessarily undergoing biopsy will be essential in reducing workload and streamlining services. This study demonstrates some key predictive factors for patients with positive biopsies. The study also shows that a large proportion of biopsies taking place do not result in the recommended length of specimen, but this does not necessarily reduce the likelihood of a positive biopsy.

The aetiology and associations of conjunctival intraepithelial neoplasia.

AIM: To summarise the main causes and associations of conjunctival intraepithelial neoplasia (CIN) found in the literature to date. METHOD: Literature search using Ovid databases on the NHS Scotland E-library, Medline, and the Cochrane Library. The internet search engine Google Scholar was also used to identify relevant articles. RESULTS: The main causes and associations of CIN in the literature are sun exposure and distance from the equator; human papillomavirus infection, increased p53 expression, and HIV seropositivity. It has been found that in HIV positive individuals CIN is on the increase with people being affected with more aggressive tumours at younger ages. CONCLUSION: Given that CIN is becoming more common in HIV infected populations and that it has the potential to cause severe disability, it is important to improve our understanding of the condition. Early identification of CIN by an understanding of its aetiology and associations may enable the implementation of preventative measures to reduce its incidence and potentially lead to the diagnosis and further management of conditions such as HIV. Young people presenting with CIN in particular may benefit from HIV testing.

"Worm in the eye": the rationale for treatment of DUSN in south India.

AIM: To discuss the rationale for different techniques of treatment for DUSN (diffuse unilateral subacute neuroretinitis) and their effectiveness in two patients from south India. METHODS: Two rare cases of live worms in DUSN from India are reported, where filarial Brugia malayi is endemic. Both cases presented with progressive unilateral loss of vision with no history of animal contact. They were 40 year old, apparently healthy men. In case 1, the worm (1500-2000 microm) was easy to identify with wriggling movements among crisscrossing diffuse subretinal tracks. The worm was destroyed by a single shot of laser to its advancing end, which was followed by oral steroid to control the inflammation caused by the dead worm. In case 2, the worm was small and difficult to identify. Initially diffuse neuroretinitis was diagnosed and treated with intravenous methylprednisolone and oral corticosteroid. A week later, a small live worm (400-600 microm) was found and subsequently destroyed by laser photocoagulation followed by a combination of anthelminthics. RESULTS: The patients' vision had improved to 6/60-6/36 from counting fingers after a few weeks. CONCLUSION: The role of a combination of laser treatment, systemic steroid, and anthelminthics is discussed.

Oral misoprostol for prevention of postpartum hemorrhage by paramedical workers in India.

OBJECTIVE: To study whether paramedical workers from rural primary health centers in India are able to administer oral misoprostol and actively manage the third stage of labor to prevent postpartum hemorrhage (PPH). METHOD: Cluster randomization was used to enroll 1200 women at 30 peripheral health centers from 5 states in India, 600 forming the study's intervention group (active management of the third stage of labor with 600 mug of oral misoprostol) and 600 forming the comparison group (in which the current government guidelines for the prevention of PPH were followed). The primary outcome was blood loss after delivery, which was measured using a calibrated blood collection drape. RESULTS: Age, literacy level, occupation, and gravidity were similar in the 2 groups. More than 70% of women in both groups had moderate anemia (hemoglobin level <10 g/dL). Paramedical workers followed instructions in almost all deliveries in the intervention group (99%). There was a significant reduction in duration of the third stage of labor (7.9 +/- 4.2 min vs. 10.9 +/- 4.3 min; p < .001) and median blood loss after delivery (100 mL vs. 200 mL; p < .001) in the intervention group. Overall, a low incidence of PPH was observed (<1%) in both groups. A greater number of women had moderate to severe shivering (12.7% vs. 0.5%) and a temperature higher than 38 degrees C (9.7% vs. 4.3%) in the intervention group, which was statistically significant. CONCLUSION: Simple interventions can be easily implemented in rural health care settings to reduce the blood loss during labor. This finding has significant implications for developing countries, in which the prevalence of anemia is high.

Prevalence of anemia among pregnant women and adolescent girls in 16 districts of India.

BACKGROUND: Nutritional anemia is one of India's major public health problems. The prevalence of anemia ranges from 33% to 89% among pregnant women and is more than 60% among adolescent girls. Under the anemia prevention and control program of the Government of India, iron and folic acid tablets are distributed to pregnant women, but no such program exists for adolescent girls. OBJECTIVE: To assess the status of anemia among pregnant women and adolescent girls from 16 districts of 11 states of India. METHODS: A two-stage random sampling method was used to select 30 clusters on the basis of probability proportional to size. Anemia was diagnosed by estimating the hemoglobin concentration in the blood with the use of the indirect cyanmethemoglobin method. RESULTS: The survey data showed that 84.9% of pregnant women (n = 6,923) were anemic (hemoglobin < 110 g/L); 13.1% had severe anemia (hemoglobin < 70 g/L), and 60.1% had moderate anemia (hemoglobin > or = 70 to 100 g/L). Among adolescent girls (n = 4,337)from 16 districts, the overall prevalence of anemia (defined as hemoglobin < 120 g/L) was 90.1%, with 7.1% having severe anemia (hemoglobin < 70 g/L). CONCLUSIONS: Any intervention strategy for this population must address not only the problem of iron deficiency, but also deficiencies of other micronutrients, such as B12 and folic acid and other possible causal factors.

Weekly iron folic acid supplementation plays differential role in maintaining iron markers level in non-anaemic and anaemic primigravida: A randomized controlled study.

Anaemia during pregnancy is most commonly observed and highly prevalent in South-East Asia. Various effective programmes have been laid down for its management, mainly daily supplementation of iron folic acid (IFA) tablets. Following the same, standard obstetrical practice has included the IFA supplementation without requiring the determination of iron deficiency. In this study, a total of 120 primigravida (N = 60; non-anaemic (Hb > 11 g/dl) and N = 60 anaemic (Hb = 8-11 g/dl)) were selected among those attending the Antenatal Clinic in Department of Obstetrics and Gynaecology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India. They were supplemented with daily and weekly IFA tablets till 6 weeks postpartum. Corresponding changes in haemoglobin level on advance of pregnancy, side effects and compliance associated with daily and weekly IFA supplementation and its associations with iron status markers were studied. The inflammatory markers were also estimated. The statistical significance level (p < 0.05) between the groups were assessed by applying unpaired t-test using SPSS (version 16.0). The obtained results publicized the salutary role of daily IFA supplementation in improving the haemoglobin level and iron status markers in anaemic pregnant women though the levels could not reach up to the non-anaemic haemoglobin levels. However, weekly IFA supplementation seems to be a better approach in non-anaemic pregnant women where almost comparable results were obtained in terms of haematological parameters, gestation length and birth weight. CONCLUSION: Weekly IFA supplementation found to be as effective as daily supplementation in iron sufficient non-anaemic pregnant women whereas anaemic pregnant women should be prescribed daily IFA supplementation irrespective of iron replete/deplete state.

Evolving concepts on the pathogenic mechanisms of aniridia related keratopathy.

Heterozygosity for PAX6 deficiency (PAX6+/-) results in aniridia. Corneal changes in aniridia-related keratopathy (ARK) include corneal vascular pannus formation, conjunctival invasion of the corneal surface, corneal epithelial erosions and epithelial abnormalities, which eventually result in corneal opacity and contribute to visual loss. Corneal changes in aniridia have been attributed to congenital deficiency of corneal limbal stem cells. The aim of this paper is to review the potential mechanisms that may underlie the pathogenesis of aniridia related keratopathy. Current evidence, based on clinical observations and an animal model of aniridia suggest that the proliferative potential of the corneal limbal stem cells may not primarily be impaired. The corneal changes in aniridia may be related to an abnormality within the limbal stem cell niche. The mechanisms underlying progressive corneal pathology in aniridia appear multi-factorial and include: (1) abnormal corneal healing responses secondary to anomalous extracellular matrix metabolism; (2) abnormal corneal epithelial differentiation leading to fragility of epithelial cells; (3) reduction in cell adhesion molecules in the PAX6 heterozygous state, rendering the cells susceptible to natural shearing forces; and (4) conjunctival and corneal changes leading to the presence of cells derived from conjunctiva on the corneal surface.

Bone-anchored hearing aids and unilateral sensorineural hearing loss: why do patients reject them?

OBJECTIVES: This study aimed to report the bone-anchored hearing aid uptake and the reasons for their rejection by unilateral sensorineural deafness patients. METHODS: A retrospective review of 90 consecutive unilateral sensorineural deafness patients referred to the Greater Manchester Bone-Anchored Hearing Aid Programme between September 2008 and August 2011 was performed. RESULTS: In all, 79 (87.8 per cent) were deemed audiologically suitable: 24 (30.3 per cent) eventually had a bone-anchored hearing aid implanted and 55 (69.6 per cent) patients declined. Of those who declined, 26 (47.3 per cent) cited perceived limited benefits, 18 (32.7 per cent) cited reservations regarding surgery, 13 (23.6 per cent) preferred a wireless contralateral routing of sound device and 12 (21.8 per cent) cited cosmetic reasons. In all, 32 (40.5 per cent) suitable patients eventually chose the wireless contralateral routing of sound device. CONCLUSION: The uptake rate was 30 per cent for audiologically suitable patients. Almost half of suitable patients did not perceive a sufficient benefit to proceed to device implantation and a significant proportion rejected it. It is therefore important that clinicians do not to rush to implant all unilateral sensorineural hearing loss patients with a bone-anchored hearing aid.

Long-term visual outcomes of intravitreal ranibizumab treatment for wet age-related macular degeneration and effect on blindness rates in south-east Scotland.

AIMS: To evaluate patient visual acuity outcomes and blindness rates attributable to wet AMD with a potential 5-year follow-up from intravitreal ranibizumab treatment (IVTR) in south-east Scotland. METHODS: Data was analysed from 104 eyes of 96 patients who initiated treatment prior to September 2008. The main outcome measures were LogMAR visual acuity, number of clinic visits and the number of injections. Annual blind registration data in south-east Scotland were analysed using blind certifications recorded by the Royal National Institute of Blind People. RESULTS: Patients had a mean clinical follow-up of 4 years and 1 month and a mean loss of 5.5 letters over the study period. Of the treated eyes 9.6% gained ≥ 15 letters whilst 24.0% lost ≥ 15 letters during this period. An average of 9.56 injections were administered per patient. The age-sex standardised incidence of legal blindness attributable to wet AMD in south-east Scotland peaked at 9.1 cases per 100,000 of the population in 2006 in either eye. Following the introduction of IVTR there were annual decreases in the incidence of blindness attributable to AMD falling to a trough of 4.8 cases per 100,000 of the population in 2011. CONCLUSIONS: This study demonstrates that the majority of patients in a south-east Scotland maintain their vision following IVTR in wet AMD in the real-world setting. Our study also suggests that the introduction of IVTR has had population wide benefits in reducing the blindness attributable to wet AMD in the south-east Scotland population.

Real-time quantitative monitoring of hiPSC-based model of macular degeneration on Electric Cell-substrate Impedance Sensing microelectrodes.

Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world. Humanized disease models are required to develop new therapies for currently incurable forms of AMD. In this work, a tissue-on-a-chip approach was developed through combining human induced pluripotent stem cells, Electric Cell-substrate Impedance Sensing (ECIS) and reproducible electrical wounding assays to model and quantitatively study AMD. Retinal Pigment Epithelium (RPE) cells generated from a patient with an inherited macular degeneration and from an unaffected sibling were used to test the model platform on which a reproducible electrical wounding assay was conducted to model RPE damage. First, a robust and reproducible real-time quantitative monitoring over a 25-day period demonstrated the establishment and maturation of RPE layers on the microelectrode arrays. A spatially controlled RPE layer damage that mimicked cell loss in AMD disease was then initiated. Post recovery, significant differences (P < 0.01) in migration rates were found between case (8.6 ± 0.46 µm/h) and control cell lines (10.69 ± 0.21 µm/h). Quantitative data analysis suggested this was achieved due to lower cell-substrate adhesion in the control cell line. The ECIS cell-substrate adhesion parameter (α) was found to be 7.8 ± 0.28 Ω(1/2)cm for the case cell line and 6.5 ± 0.15 Ω(1/2)cm for the control. These findings were confirmed using cell adhesion biochemical assays. The developed disease model-on-a-chip is a powerful platform for translational studies with considerable potential to investigate novel therapies by enabling real-time, quantitative and reproducible patient-specific RPE cell repair studies.