Using complex networks towards information retrieval and diagnostics in multidimensional imaging.

We present a fresh and broad yet simple approach towards information retrieval in general and diagnostics in particular by applying the theory of complex networks on multidimensional, dynamic images. We demonstrate a successful use of our method with the time series generated from high content thermal imaging videos of patients suffering from the aqueous deficient dry eye (ADDE) disease. Remarkably, network analyses of thermal imaging time series of contact lens users and patients upon whom Laser-Assisted in situ Keratomileusis (Lasik) surgery has been conducted, exhibit pronounced similarity with results obtained from ADDE patients. We also propose a general framework for the transformation of multidimensional images to networks for futuristic biometry. Our approach is general and scalable to other fluctuation-based devices where network parameters derived from fluctuations, act as effective discriminators and diagnostic markers.

Hyperhomocysteinemia, a biochemical tool for differentiating ischemic and nonischemic central retinal vein occlusion during the early acute phase.

PURPOSE: The purpose of the study was to differentiate ischemic central retinal vein occlusion (CRVO) from nonischemic CRVO during the early acute phase using plasma homocysteine as a biochemical marker. METHODS: Fasting plasma homocysteine, serum vitamin B12, and folate levels were measured in 108 consecutive unilateral elderly adult (age >50 years) ischemic CRVO patients in the absence of local and systemic disease and compared with a total of 144 age and sex matched nonischemic CRVO patients and 120 age and sex matched healthy control subjects. RESULTS: Homocysteine level was significantly increased in the patients with ischemic CRVO in comparison with nonischemic CRVO patients (p = 0.009) and also in comparison with control subjects (p < 0.001). Analysis also showed that hyperhomocysteinemia was associated with increased incidence of ischemic CRVO (odds ratio, 18) than that for nonischemic CRVO (odds ratio, 4.5). Serum vitamin B12 and folate levels were significantly lower (p < 0.001) in CRVO patients compared to the control but were not significantly different between nonischemic and ischemic CRVO patients (p > 0.1). CONCLUSIONS: Hyperhomocysteinemia can be regarded as useful in differentiating nonischemic and ischemic CRVO during the early acute phase in absence of local and systemic disease in the elderly adult (age >50 years) population.

Dry eye: a protein conformational disease.

PURPOSE: The purpose of this study was to determine whether aqueous-deficient dry eyes (ADDE) is a protein conformational disease. Up to now the therapeutic regimen has been based on empirical results, but these observations may unfold new theranostic approaches for ADDE management. METHODS: Fifty ADDE patients and 46 healthy volunteers were recruited. Schirmer's test, tear breakup time, tear meniscus height, and fluorescein staining tests were conducted on the subjects. Tear protein for ADDE and control patients was collected and extracted using Schirmer's strip. Protein aggregation was studied by appraisal of average protein size, using dynamic light scattering (DLS), fast performance liquid chromatography (FPLC), and synchronous fluorescence spectroscopy (SFS). RESULTS: Dynamic light scattering data showed a comparatively higher abundance of aggregated proteins in ADDE patients than that in controls. For controls, the size distribution of tear proteins was <50 nm in diameter, whereas the size distribution for ADDE individuals was up to 300 nm in diameter. Fast performance liquid chromatography experiments in native tear proteins exhibited minimal difference in the FPLC profiles for ADDE patients and controls. Denatured tear protein FPLC profiles for patients indicated the presence of protein aggregates which were absent in controls. Our hypothesis was further verified by SFS; lower tryptophan fluorescence in ADDE patients is an indication of oxidative stress, which leads to protein aggregation. CONCLUSIONS: Aqueous-deficient dry eyes is likely to be a protein conformational disease. Unlike other conformational diseases where single proteins are involved, this may be a reflection of structural loss for a significant fraction of the tear proteome.

Penetrating keratoplasty restoring vision in an unusual case of corneal opacity following exposure to Euphorbia latex.

The milky sap of the Euphorbia plant is highly toxic and causes inflammation to the skin and eyes. Damage to the eye ranges from superficial epithelial defects, keratoconjunctivitis, mild to moderate corneal edema, anterior uveitis, Descemet membrane folds, raised intraocular pressure and rarely corneal opacity in severe untreated cases. Here we report a case of visual restoration by optical penetrating keratoplasty in a patient with severe corneal opacity following exposure to Euphorbia latex.

Comparative role of 20% cord blood serum and 20% autologous serum in dry eye associated with Hansen's disease: a tear proteomic study.

BACKGROUND: To compare the role of topically applied serum therapy with preservative-free artificial tear (AT) drops in patients with moderate to severe dry eye in Hansen's disease along with change in tear protein profile. METHODS: 144 consecutive patients were randomly divided into three groups. After a baseline examination of clinical parameters, each of the patients received designated modality of topical therapy six times a day for 6 weeks. Post-treatment documentation of clinical parameters was done at 6 weeks, and then at 12 weeks after discontinuation of topical therapy. Analysis of three tear proteins using gel electrophoresis (sodium dodecyl sulfate polyacrylamide gel electrophoresis) was done at baseline, at the first and second post-treatment visits. RESULTS: In the cord blood serum (CBS) group, except for McMonnies score and staining score, all other clinical parameters showed continued improvement in the first and second post-treatment analyses. In the autologous serum (ALS) group, all the clinical parameters except Schirmer's I showed significant improvement in the first post-treatment analysis .This was sustained at a significant level in the second analysis except for tear film break-up time (TBUT) and conjunctival impression cytology grading. In the AT group, all the parameters improved at a non-significant level except for TBUT in the first analysis. In the next analysis, apart from McMonnies score and TBUT, other clinical parameters did not improve. In the ALS and CBS groups, tear lysozyme, lactoferrin levels improved in both post-treatment measurements (statistically insignificant).Total tear protein continued to increase at statistically significant levels in the first and second post-treatment analyses in the CBS group and at a statistically insignificant level in the ALS group. In the AT group, the three tear proteins continued to decrease in both the analyses. CONCLUSIONS: In moderate to severe dry eye in Hansen's disease, serum therapy in comparison with AT drops, improves clinical parameters and causes betterment in tear protein profile. TRIAL REGISTRATION NUMBER: CTRI/2013/07/003802.

Intracorneal rhinosporidiosis managed with deep anterior lamellar keratoplasty.

A healthy 22-year-old male presented to Institutional Cornea Clinic with an intracorneal mass overlying the pupil with lobulated edges having many tiny greyish white dots. The patient had a history of trauma while swimming in a pond with subsequent removal of intracorneal foreign body in the left eye approximately a year prior to presentation. Anterior segment optical coherence tomography (OCT) confirmed that an intracorneal mass sparing deep stroma and Descemet's membrane. A deep anterior lamellar keratoplasty (DALK) was performed in left eye and the mass was sent for histology examination. Histology evaluation was suggestive of rhinosporidiosis. The patient achieved 20/60 BCVA with -1.25 Χ× 120° 1 year postoperatively without any evidence of recurrence at the graft-host interface. This unique presentation (as an 'intracorneal mass') of ocular rhinosporidiosis emphasizes that clinicians from our region of the world must consider rhinosporidiosis in the differential diagnosis especially with a history of penetrating injury while swimming in pond or river water.

Change in tear protein profile in diabetic retinopathy with duration of diabetes.

AIMS: To study change in tear protein profile with duration of diabetes and severity of diabetic retinopathy (DR) in type 2 diabetes patients. MATERIALS AND METHODS: Tear protein profile was ascertained by SDS PAGE method in 30 patients with DR (group A) and 37 patients without DR (group B). RESULTS: Six distinct bands of proteins were identified; these proteins are as follows: 91kDa (P1), 66kDa (P2), 60kDa (P3), 30kDa (P4), 18.4kDa (P5) and 14.4kDa (P6). Prevalence of P3 was significant (p=0.036) in group A, especially in cases with diabetes ≤8 years compared with diabetes >8 years (p=0.0107). In group B, P2 was significantly prevalent (p<0.0013) in cases with diabetes ≤8 years compared to diabetes >8 years. Considering the changes in terms of duration of diabetes in general, patients with diabetes of ≤8 years, P3 was significantly prevalent in group A compared to group B (p=0.004); and when the duration of diabetes is >8 years, P2 was found significantly more in group A compared to group B (p=0.01). No significant difference in P3 (p=0.025), P4 (p=0.2877), P5 (p=0.4801), P6 (p=0.0985) was observed in mild to moderate NPDR group compared to severe NPDR to PDR group. P1 and P2 were present only in severe NPDR and PDR. CONCLUSION: Variable protein expression was observed with duration of diabetes and severity of diabetic retinopathy.

Reference interval determination of total plasma homocysteine in an Indian population.

Hyperhomocysteinemia has been shown to be an independent risk factor for cardiovascular disease as well as retinal vascular occlusion. Because of the epidemiological, dietary, genetic and environmental diversity among the different countries, each country should establish the reference interval of homocysteine of their own population for recommending appropriate medical decision limits. Hence a total of 1,288 apparently healthy subjects including 636 male and 652 female were enrolled in the present study to determine the reference intervals of homocysteine in an Indian population. Results of the study were presented as mean, standard deviation, median and 2.5th and 97.5th percentile with the 0.90 confidence interval of each percentile values of homocysteine along with decade-wise changes.

Thermal fluctuation based study of aqueous deficient dry eyes by non-invasive thermal imaging.

In this paper we have studied the thermal fluctuation patterns occurring at the ocular surface of the left and right eyes for aqueous deficient dry eye (ADDE) patients and control subjects by thermal imaging. We conducted our experiment on 42 patients (84 eyes) with aqueous deficient dry eyes and compared with 36 healthy volunteers (72 eyes) without any history of ocular surface disorder. Schirmer's test, Tear Break-up Time, tear Meniscus height and fluorescein staining tests were conducted. Ocular surface temperature measurement was done, using an FL-IR thermal camera and thermal fluctuation in left and right eyes was calculated and analyzed using MATLAB. The time series containing the sum of squares of the temperature fluctuation on the ocular surface were compared for aqueous deficient dry eye and control subjects. Significant statistical difference between the fluctuation patterns for control and ADDE was observed (p < 0.001 at 95% confidence interval). Thermal fluctuations in left and right eyes are significantly correlated in controls but not in ADDE subjects. The possible origin of such correlation in control and lack of correlation in the ADDE subjects is discussed in the text.

Comparison of autologous in situ blood coagulum versus sutures for conjunctival autografting after pterygium excision.

Our aim was to compare the efficacy and safety of autologous in-situ blood coagulum versus sutures for attaching conjunctival limbal autografts (CAG) among patients undergoing primary pterygium excision over a period of 1 year. Thirty-two eyes of 32 patients with primary pterygium were randomly divided in into two groups: group I (16 eyes) underwent CAG with 10-0 monofilament nylon sutures and group II (16 eyes) underwent CAG with patient's own in-situ blood coagulum acting as bioadhesive or fixative followed by bandaging for 48 h. Patients were followed up postoperatively on the 2nd day, 1 week, 2 weeks, 4 weeks, and 12 months. All the surgeries were done by the same surgeon. Graft success, recurrence rate, operating time, patient comfort, graft retraction or any other complication were studied. The duration of surgery was significantly less (P < 0.001) in group II (mean duration 15 ± 2 min) than group I (mean duration 67 ± 2 min). Postoperative symptoms were fewer for group II than group I. Rate of recurrence was equal in both groups (one patient in each group, 6.25 %). But complications regarding graft failure and graft retraction were more common in group II (two patients, 12.5 %) than group I (one patient, 6.25 %); however, the difference was not statistically significant (Z = 0.61). Thus, autologous in-situ blood coagulum is a useful method for graft fixation in pterygium surgery with shorter operating time and less postoperative discomfort.

Corneal penetration of gold nanoparticles--therapeutic implications.

Gold nanoparticles can show anti-glycation activity thereby preventing the aggregation of proteins. As glycation is one of the leading causes of cataract formation, the finding is important in therapeutic management of ocular pathology that follows cataract formation (e.g., cortical changes often resulting in nuclear sclerosis). In the present study, we have successfully conducted in vivo experiments using guinea pig models. While the anti-glycation property of GNPs is known in vitro, the present work for the first time shows corneal penetration of GNPs. The therapeutic promise of using GNP as an anti-cataract agent thus seems imminent. GNPs traverse and get deposited into different layers of the cornea as examined by Transmission Electron Microscopy (TEM).

Comparison of ex vivo cultivated human limbal epithelial stem cell viability and proliferation on different substrates.

Ocular surface injury causes serious vision-related problems especially when limbal stem cells are affected. Treatment lies in the transplantation of viable donor cells. Various substrates are used for the cultivation of limbal epithelial stem cells. In the present study, viability and proliferation of ex vivo cultured limbal epithelial stem cells were examined on a variety of substrates like collagen type IV, direct plastic Petri plate, intact amniotic membrane and denuded amniotic membrane. Viability and proliferation of cells were examined by colorimetric assay and [(3)H]-thymidine incorporation study. Furthermore, matrix metalloproteinase is known to be a key regulator in stem cell migration and proliferation. This enzyme activity was studied by gelatinolytic zymography. It was found from this study that although human limbal epithelial stem cells could be cultivated on different substrates such as collagen type IV, direct plastic Petri plate, intact amniotic membrane and denuded amniotic membrane, maximum growth and proliferation was observed when cultured on intact amniotic membrane. The number of patients suffering from limbal epithelial stem cell deficiency is large compared to donor tissues available for transplantation. Hence, increased cell viability and proliferation is required to serve more patients.

An impression cytology based study of ocular surface in an urban population.

To assess the health of ocular surface in a defined urban population, conjunctival goblet cell density and degree of surface squamous metaplasia were utilized as study tools. Two thousand names of those aged between 20 and 79 years from the 2006 electoral register in ward number 63 of Kolkata Corporation area were initially selected. Normal healthy human volunteers without any history of ocular surface disorder were recruited and divided into five age-groups. Impression cytology samples were obtained from interpalpebral part of bulbar conjunctiva from all the participants fixated and stained by a single observer. A stratified, clustered, disproportionate, random sampling method was used. The software used in the statistical analysis was EPI Info. The tests applied were t test and ANOVA. A variation in the number of goblet cells according to gender (women having less cells) and age (20-30 years group having the highest number of cells) was found. Those working outdoors were found to have fewer goblet cells compared to those who stay indoors. The majority of the people had grade 1 cytological appearance in both males and females. There was no statistically significant difference in Nelson's grading with age. People using coal and kerosene to cook were found to have a smaller goblet cell density than those who cooked on LPG or those who did not cook at all. Besides age and sex, environmental factors like the method of cooking and occupational variables (like outdoor activity, prolonged period of computer use, etc.) modify the health of the ocular surface. The results of this study will help put these findings into perspective as public health problems.

Hyperhomocysteinemia, as an independent risk factor for retinal venous occlusion in an Indian population.

Total plasma homocysteine was analysed in 64 cases of retinal vein occlusion (RVO) of which 24 cases of central retinal vein occlusion (CRVO) and 40 cases of branch retinal vein occlusion (BRVO) and compared with 45 age and sex matched control. Homocysteine was significantly increased in RVO cases in respect to control (P < 0.001). Analysis also revealed that prevalence of rise of plasma homocysteine was more in cases of CRVO (OR = 13) than that of BRVO (OR = 5.03).

Boston keratoprosthesis restoring vision in an unusual case of end-stage limbal stem cell deficiency following exposure to Euphorbia latex.

We report the functional outcome of a patient who had undergone Boston keratoprosthesis type I for extensive ocular surface damage caused by latex of Euphorbia. The milky sap or latex of the Euphorbia plant is highly toxic and an irritant to the skin and eye. Damage to the eye ranges from mild to severe corneal edema, epithelial defects, anterior uveitis, secondary elevated intraocular pressure and, rarely, limbal stem cell deficiency with corneal neovascularization. A restrospective review was conducted of this patient for more than 1 year. During this period he was given subconjunctival bevacizumab injection to regress the corneal vascularization without much benefit, before finally performing Boston keratoprosthesis type I. The patient was evaluated periodically for both anatomical and visual outcome. At the end of 1-year follow-up the keratoprosthesis is well retained with a best-corrected visual acuity of 20/40 in the affected eye.

Effect of cord blood serum on ex vivo human limbal epithelial cell culture.

Limbal cell transplantation is an efficacious procedure for rehabilitation of visual acuity in patients with severe ocular surface disorders. Cultivation of limbal epithelial stem cell with fetal bovine serum for transplantation has been a promising treatment for reconstructing the ocular surface in severe limbal stem cell deficiency caused by Steven Johnson syndrome, chemical or thermal injury. This technique of "cell therapy" has been accepted worldwide but the cost of cultivating the cells for transplantation is high. The objective of this study was to investigate the effect of cord blood serum in place of fetal bovine serum on the growth of human limbal epithelial cell culture. Our group has experimented with human cord blood serum which was obtained free of cost from willing donors. The use of human cord blood serum in place of fetal bovine serum for ex vivo culture of limbal stem cell has helped us in reducing the cost of culture. Fresh human limbal tissues from donor cadavers were cultured on intact and denuded amniotic membrane. Cells were proliferated in vitro with cell culture media containing human cord blood serum. Reverse transcription-polymerase chain reaction and immunofluorescence cytochemistry of cultured human limbal epithelial stem cell was done for characterization of the cells.

Gold nanoparticle induces masking of amines and some therapeutic implications.

Citrate capped gold nanoparticles (GNP) are effective in masking protein amines. The extent of such masking is quantified using Fourier Transform Infra Red (FTIR) spectroscopy. A strong correlation is shown to exist between a shift of amide-II peak intensity (1600-1500 cm(-1)) caused by GNP and the number of exposed amines in a given protein. The result is validated using eight different proteins. The expected out-come of such masking is inhibition of interaction between any external ligand and such amines. The prediction is validated using a simple non-enzymatic glycation of clinically important protein like crystallin.

Size dependent chaperon properties of gold nanoparticles.

Citrate synthase is a heat labile enzyme showing a loss of activity even in response to a modest shift of temperature (35 degrees-45 degrees C). Gold nanoparticle is shown to prevent the thermal aggregation of this enzyme. The chaperon like activity of the nanoparticle diminishes if the particle size is reduced from 40 nm to 20 nm keeping the atomic concentration of gold constant. This implies that the effect is not merely due to enhanced surface area offered by the nano-surfaces. The effect is reversible as the protein separated out from nanoparticles behaves similar to control. The observed coupling between chaperon activity of the nanoparticle and its cluster forming ability is illustrated in terms of a thermal cage model.