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Biomedical subjects

Mahesh P Shanmugam

Publications and source records attributed to Mahesh P Shanmugam.

At least 19 recordsLinked to original sources

A prospective randomised trial of different doses of intravitreal triamcinolone for diabetic macular oedema.

OBJECTIVE: To compare the safety and efficacy of different doses of intravitreal triamcinolone (ivTA) in treating clinically significant diabetic macular oedema (CSMO). METHODS: 63 eyes of 63 patients with CSMO and central foveal thickness (CFT) of > or =250 microm on optical coherence tomography were randomised to receive 4 mg (n = 23), 6 mg (n = 20) or 8 mg (n = 20) ivTA. Patients were followed up for 6 months, and changes in best-corrected visual acuity (BCVA), optical coherence tomography CFT, standardised change in macular thickness (SCMT), and side effects such as intraocular pressure and cataractogenesis were compared between the three groups. RESULTS: After ivTA injection, improvements of BCVA and CFT occurred in all groups. The mean BCVA improvement at 6 months was significantly higher for the 8 mg group compared with the 4 mg group, with 9.9 and 3.1 improvement in letters on the Early Treatment of Diabetic Retinopathy Study chart, respectively (p = 0.047). The mean SCMT at 6 months for the 4, 6 and 8 mg groups was 28.7%, 42.3% and 60.5%, respectively (p = 0.06). The proportion of eyes with SCMT > or =75% at 6 months was higher in the 8 mg group, but the difference failed to reach significance (p = 0.06). Ocular hypertensive responses (>21 mm Hg) occurred in 39%, 30% and 55% of eyes in the 4, 6, and 8 mg groups, respectively (p = 0.27). CONCLUSIONS: Higher doses of ivTA may prolong the duration of visual benefit in diabetic CSMO and seemed to result in more sustained reduction in macular oedema. Further studies are warranted to investigate the optimum dose of ivTA in treating diabetic CSMO.

Aged↗

Pars plana vitrectomy and perfluoropropane (C3F8) tamponade for retinal detachment due to myopic macular hole: a prognostic factor analysis.

PURPOSE: To determine the prognostic factors associated with anatomical success in the treatment of retinal detachment (RD) due to myopic macular hole by pars plana vitrectomy (PPV) and perfluoropropane (C3F8) gas tamponade. DESIGN: Retrospective, interventional, comparative case series. METHODS: In an institutional setting, 57 eyes with myopic macular hole RDs treated by PPV and C3F8 tamponade, with or without concomitant internal limiting membrane (ILM) peeling, endolaser photocoagulation, and/or phacoemulsification, were analyzed. Outcome measures were anatomical success, defined as closure of macular hole with reattachment of the surrounding retina, and postoperative best-corrected visual acuity (BCVA). RESULTS: The mean postoperative follow-up was 26.9 +/- 16.5 months. The anatomical success rate after primary PPV and C3F8 tamponade was 63.2%. Regression analysis showed that shorter axial lengths (odds ratio [OR] = 6.73, 95% confidence interval [95% CI] 1.86 to 12.22, P = .010), concomitant ILM peeling (OR 1.59, 95% CI 1.14 to 2.38, P = .013), and shorter duration of macular hole RD (OR 0.81, 95% CI 0.67 to 0.98, P = .033) were associated with a higher anatomical success. The mean pre- and postoperative BCVAs were 1.430 +/- 0.273 (range, 0.523 to 1.700) and 1.403 +/- 0.271 (range, 0.699 to 1.800) logarithm of minimal angle of resolution units, respectively. The postoperative BCVA was significantly better in eyes with macular hole closure than in eyes without (P = .021). CONCLUSIONS: Axial length, concomitant ILM peeling, and duration were important prognostic factors for PPV and C3F8 tamponade in the treatment of myopic macular hole RDs.

Adult↗

Visual outcome after discontinuation of corticosteroids in atypical severe central serous chorioretinopathy.

PURPOSE: To elucidate the effect of discontinuation of corticosteroids in patients with atypical severe central serous chorioretinopathy (CSC) on retinal reattachment, resolution of retinal pigment epithelium (RPE) leaks, and improvement in visual acuity (VA). DESIGN: Prospective, noncomparative, observational case series. PARTICIPANTS: Twenty-four eyes of 17 patients who were being treated with corticosteroids for atypical severe CSC. Of these 17 patients, 16 were treated inappropriately with corticosteroids for their ocular condition; presumably, these patients' conditions were misdiagnosed, and they were thought to have choroiditis, Harada's syndrome, or similar entities, and not central serous chorioretinopathy. INTERVENTION: Observation or laser photocoagulation. MAIN OUTCOME MEASURES: Reattachment of the retina, obliteration of RPE leaks on fundus fluorescein angiography, and improvement in Snellen VA. RESULTS: Discontinuation of corticosteroids resulted in reattachment of the retina in 21 eyes (87.5%), with median time to reattachment of 49 days (range, 32-400); only 3 eyes required laser photocoagulation. Fundus fluorescein angiography showed obliteration of RPE leaks at a median period of 75 days (range, 32-400) in the observed eyes; the median VA improved from 20/80 to 20/30. The mean follow-up was 16.5 months. CONCLUSIONS: Discontinuation of corticosteroids in atypical CSC helped in obliteration of RPE leaks and retinal reattachment in 87.5% of the eyes without laser treatment, and improvement in VA was observed.

Adult↗

Retinoblastoma presenting as orbital cellulitis: report of four cases with a review of the literature.

PURPOSE: To analyze the clinical and histopathological features of retinoblastoma presenting as orbital cellulitis. MATERIAL AND METHODS: Retrospective analysis of case records and review of the histopathology of four patients with retinoblastoma presenting as orbital cellulitis.RES U LTS On histopathological examination, all eyes showed anterior segment involvement with extensive necrosis. One case had a well-differentiated tumor and one showed extraocular extension of the tumor. CONCLUSION: Advanced necrotic retinoblastoma with anterior segment involvement may often present as orbital cellulitis.

Anterior Eye Segment↗

Nm23 expression in retinoblastoma.

PURPOSE: Nm23 is a metastasis-suppressor protein. Decreased nm23 protein contributes to aggressiveness in many tumors. Nm23 immunoreactivity was studied in retinoblastoma and correlated with differentiation and invasiveness. METHODS: Immunohistochemistry was performed on 73 formalin-fixed, paraffin-embedded specimens of retinoblastoma. Western blot was conducted to confirm the immunohistochemical study. Prognostic features such as differentiation, invasion of choroid, optic nerve, and orbit, and metastasis were analyzed. RESULTS: Intense nm23 immunoreactivity was seen in 61% of the retinoblastomas with no invasion and faint nm23 immunoreactivity was seen in 85% of the retinoblastomas with invasion (p < 0.001). Poorly differentiated retinoblastoma showed decreased nm23 immunoreactivity compared to well-differentiated retinoblastomas (p = 0.02). An inverse correlation was observed between invasion of choroid, optic nerve, orbit, and metastasis, and nm23 immunoreactivity. Western blot assays of fresh tumor extracts confirmed the immunohistochemical findings. CONCLUSIONS: Decreased nm23 immunoreactivity was seen in poorly differentiated retinoblastomas and in retinoblastomas with invasiveness. These findings may lay the groundwork for further studies to better understand the molecular mechanisms and provide a more accurate prediction of invasion and metastasis of retinoblastoma.

Blotting, Western↗

Clinical and histopathological characteristics of uveal melanoma in Asian Indians. A study of 103 patients.

PURPOSE: To study the clinical and histopathological characteristics of uveal melanomas in Asian Indians and compare them with other ethnic groups. MATERIALS AND METHODS: One hundred and three enucleated eyes with clinical diagnosis of uveal melanoma were retrospectively studied (1987-2001) and the clinical and pathological features analysed. RESULTS: Uveal melanomas constituted 0.02% of outpatients in a referral eye hospital in India over a 12-year period. The patients were predominantly males. Uveal melanomas tended to occur in the younger age. The mean age was 45.7 +/- 14.2 years. Melanoma involved the choroid in 90 (87.37%) patients, and both choroid and ciliary body in 13 (12.62%) patients. Mean basal diameter of the tumour was 13.43 +/- 5.32 mm. Mixed cell type was more common. CONCLUSION: Uveal melanomas are rare in the Asian Indians compared to those in the West. They occur in younger persons, have a greater mean basal diameter than that of Caucasians and are predominantly of the mixed cell type.

Asian People↗

Transpupillary thermotherapy for choroidal neovascular membrane in age related macular degeneration.

PURPOSE: To evaluate the efficacy of transpupillary thermotherapy (TTT) in choroidal neovasularisation (CNVM) secondary to age related macular degeneration (AMD). MATERIAL AND METHODS: Retrospective, non-randomized study of 28 eyes of 28 patients with subfoveal CNVM (classic, occult or mixed) secondary to AMD. RESULTS: Fifteen patients (53.57%) maintained their pre-treatment vision, 2 (7.14%) patients showed improvement of more than 2 lines and 11 (39.28%) patients showed deterioration of vision by >2 lines. Angiographic and clinical regression of CNVM was noted in 19 patients (67.8%) on an average follow up of 15.32 +/- 3.31 months. CONCLUSION: TTT leads to stabilisation of vision in 60% of treated eyes with CNVM due to AMD.

Aged↗

Intraocular cysticercosis: clinical characteristics and visual outcome after vitreoretinal surgery.

PURPOSE: To report the clinical characteristics of, discuss the surgical options for, and analyze the factors affecting the anatomic and visual outcome of intraocular cysticercosis. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Forty-five eyes of 44 Indian patients with posterior segment intraocular cysticercosis. METHODS: The charts of 45 eyes, in which intraocular cysticercosis was removed by vitreoretinal surgery (either transscleral or transvitreal), were reviewed. MAIN OUTCOME MEASURES: These included the postoperative retinal status and the best-corrected Snellen visual acuity. RESULTS: Intraocular cysticercosis was present in the vitreous cavity of 27 eyes (60%) and in the subretinal space of 18 eyes (40%). Anterior segment inflammation was seen in 13 eyes (28.8%) and vitreous inflammation in 38 eyes (84.4%). Retinal detachment was observed in 22 eyes (48.8%), with proliferative vitreoretinopathy in 13 eyes (59.09%). Subretinal cysts anterior to the equator (4 eyes) were removed transsclerally, whereas subretinal cysts posterior to the equator and intravitreal cysts (41 eyes) were removed transvitreally. The mean follow-up was 10.5 months. At the last follow-up, the retina was attached in 39 eyes (86.6%); visual acuity of >/=5/200 was achieved in 67.5%. CONCLUSIONS: Current vitreoretinal surgical techniques enable removal of intraocular cysticercosis in all cases, with reattachment of the retina in 86.6% and recovery of ambulatory vision in approximately 67% of cases.

Adolescent↗

Prognostic significance of Fas expression in retinoblastoma.

PURPOSE: The loss of Fas is believed to enhance metastatic spread in diverse human tumors. We studied the expression of Fas by immunohistochemistry in retinoblastomas and correlated the results clinicopathologically. METHODS: Archival specimens of 76 retinoblastomas were included in this study. The tumors were divided into three groups: Group A (n = 21) comprising tumors with no invasion; Group B (n = 46) tumors with invasion of choroid (diffuse), optic nerve (post-laminar), and orbit; and Group C (n = 9) tumors with both invasion and metastasis. Sections were immunostained with monoclonal antibody CD95 (APO-1/Fas) and the immunoreactivity was assessed. RESULTS: Negative immunoreactivity of Fas was observed in Group B and Group C tumors (p < 0.001). Poorly differentiated retinoblastomas showed a decreased Fas expression (p = 0.006). CONCLUSIONS: Decreased expression of Fas is seen in aggressive tumors and tumors that are poorly differentiated. This preliminary observation deserves further investigation, which may then shed more light on the immune escape mechanisms of this tumor and thus enable novel therapeutic strategies.

Humans↗

Scleral buckling: implant versus explant.

PURPOSE: To compare the implant and explant techniques of scleral buckling. METHODS: This prospective, randomized clinical study compared the two techniques of scleral buckling. Variables such as size and extent of the buckle, duration of the surgery, complications, and anatomical and visual outcome were studied. The height of the buckle as measured by ultrasonography was also studied. RESULTS: No significant difference was found between the two groups for total duration of the surgery, complications, anatomical results, visual outcome, and buckle height. For the 1- to 2-quadrant buckles, duration of the surgery up to initiation of subretinal fluid drainage was found to be significantly shorter for the explant group. Serial ultrasonography showed significant reduction in buckle height over 6 months in both groups to an equal degree. CONCLUSIONS: Scleral buckling seems to be equally effective whether performed as an implant or explant.

Adult↗