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Biomedical subjects

M P Shanmugam

Publications and source records attributed to M P Shanmugam.

At least 19 recordsLinked to original sources
PubMed2006

Decreasing efficacy of repeated intravitreal triamcinolone injections in diabetic macular oedema.

BACKGROUND/AIM: Intravitreal triamcinolone (IVTA) results in transient improvements in diabetic macular oedema (DMO), necessitating repeated injections. The authors report a case series of 10 eyes of 10 patients with DMO, who received a repeat injection of 4 mg IVTA, at least 26 weeks after the first injection of the same dose. METHOD: Pre-injection and at 2, 4, 9, and 17 weeks post-injection, best corrected visual acuity (BCVA) and central foveal thickness (CFT) on optical coherence tomography, after the first and repeat injections, were compared using paired t test. Side effects were monitored. RESULTS: BCVA, CFT, intraocular pressure (IOP), and cataract scores were not significantly different before initial and repeat injections (given at 32.5 (SD 3.5) weeks after the first injection). Transient improvements of BCVA and CFT were achieved after both injections. However, after the repeat injection, the BCVA was significantly worse at all time points (p<0.05) and so were the best achieved CFT and the CFT at 4 weeks post-injection (p = 0.034 and 0.011 respectively), compared with the initial injection. Post-injection maximum IOPs and increase in cataract scores were not significantly different between the two injections. CONCLUSION: A repeat injection of 4 mg of IVTA may not be as effective as an initial injection for the treatment of DMO.

Aged↗
PubMed2004

Multidrug resistant proteins: P-glycoprotein and lung resistance protein expression in retinoblastoma.

BACKGROUND/AIM: Retinoblastoma is the commonest primary intraocular tumour in children. Chemotherapy now plays a big part in the treatment of these tumours. There is not much information about the role of the multidrug resistance proteins (MDR)-P-glycoprotein (P-gp) and vault protein lung resistance protein (LRP)-in retinoblastoma. The authors investigated the expression of P-gp and LRP in retinoblastoma and correlated them clinicopathologically. METHODS: Among 60 retinoblastomas, 40 tumours were not subjected to preoperative or postoperative chemotherapy and 20 tumours were subjected to postoperative chemotherapy. In this cohort 27 tumours had no invasion and 33 tumours had invasion of choroid, optic nerve, and orbit. P-gp and LRP expression were studied by immunohistochemistry. Immunoanalysis was done semiquantitatively. RESULTS: Among the 60 tumours P-gp was expressed in 23 (38%) tumours and LRP was expressed in 35 (58%). P-gp was expressed in 11/27 (40%) tumours with no invasion and in 12/33 (36%) tumours with invasion. LRP was expressed in 15/27 (55%) tumours with no invasion and in 20/33 (60%) tumours with invasion. Both P-gp and LRP were negative in three tumours with invasion, which had later developed bone marrow metastasis. There was no correlation between P-gp and LRP expression with invasion, differentiation and laterality of the tumours and response to treatment. CONCLUSION: Retinoblastoma expresses P-gp and LRP intrinsically before chemotherapy and none of these proteins predicted the response to chemotherapy. Thus, further studies are needed to understand the significance of the expression of the P-gp and LRP proteins in retinoblastoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Congenital retinoschisis: successful collapse with photocoagulation.

We report a case of progressive congenital retinoschis is where the schisis cavity collapsed following argon laser photocoagulation. Despite reports to the contrary, we feel that in the absence of significant vitreous or inner layer traction, photocoagulation applied as light burns in the schisis cavity may be beneficial in collapsing the cavity. Whether or not this collapse of the schisis cavity reduces the risk of rhegmatogenous retinal detachment is unclear.

Humans↗
PubMed2001

Genetic profile of 81 retinoblastoma patients from a referral hospital in southern India.

PURPOSE: To determine chromosomal abnormalities and inheritance pattern in patients with retinoblastoma from a referral hospital in southern India. MATERIALS AND METHODS: Eighty-one retinoblastoma patients from 78 families were included in this study. Peripheral venous blood was taken for chromosomal analysis and pedigree was ascertained for segregation analysis. RESULTS: Male to female ratio was 1.7:1, 55.56% were bilateral retinoblastoma, the mean age of onset was 12.37 months in bilateral and 33.07 months in unilateral cases (p=0.048). Majority (90.12%) had sporadic inheritance and 6.17% had autosomal dominant inheritance. In chromosomal abnormalities, 8.33% had 13q14 deletion, three cases had de novo balanced translocations. CONCLUSION: The age of onset of the disease was much earlier in the bilateral cases compared to unilateral cases. Sporadic inheritance was predominant while only a small percentage of patients had autosomal dominant inheritance. The percentage of patients with 13q14 deletion was higher than reported in the literature and three novel chromosomal translocations were observed. This is one of the largest series of cases reported from India.

Adolescent↗
PubMed2000

Ultrasound biomicroscopy of sclerotomy sites after pars plana vitrectomy for diabetic vitreous hemorrhage.

OBJECTIVE: This study was aimed at assessing changes at the sclerotomy site using the ultrasound biomicroscope (UBM) in eyes that underwent primary pars plana vitrectomy for complications of proliferative diabetic retinopathy. DESIGN: Prospective, observational case series. PARTICIPANTS: Eighty-six eyes of 84 patients with vitreous hemorrhage caused by proliferative diabetic retinopathy. INTERVENTION: Three-port pars plana vitrectomy followed by UBM evaluation of all sclerotomy sites between 6 and 8 weeks after surgery. Correlation with intraoperative findings done in case of reoperations. Forty-one eyes had repeat UBM at 6 months. MAIN OUTCOME MEASURES: The changes at the sclerotomy site were classified into six groups: well healed, gape, plaque, vitreous incarceration, fibrovascular proliferation, and anterior hyaloidal fibrovascular proliferation (AHFVP). The UBM characteristics of each of the groups were defined. The findings at 6 months were compared with those at 6 to 8 weeks. RESULTS: At 6 to 8 weeks after surgery, most sclerotomies were well healed or had either moderate to high reflective plaques bridging the site. Wound gape was seen in 22.1% of active ports, 32.6% of light ports, and 25.6% of infusion ports. Vitreous incarceration was seen most often at the infusion port (18. 6% of eyes). Fibrovascular proliferation was seen in 9.3% of active ports, 12.8% of light ports, and 15.1% of infusion ports. Thirteen eyes had recurrent vitreous hemorrhage 6 to 8 weeks after surgery. Cases with rebleeding and no fibrovascular proliferation at the sclerotomy on UBM did well with outpatient fluid-air exchange (two eyes) or observation only (three eyes). Those with fibrovascular proliferation on UBM (eight eyes) required more extensive surgery. CONCLUSIONS: UBM is helpful in detecting complications at the sclerotomy sites after pars plana vitrectomy and is an invaluable tool in the assessment of the patient before reoperation.

Diabetic Retinopathy↗
PubMed1999

Vitreoschisis in Eales' disease: pathogenic role and significance in surgery.

PURPOSE: To report the surgical anatomy of vitreoretinal adhesions as observed intraoperatively in patients undergoing vitreous surgery for complications of Eales' disease. METHODS: Eighteen consecutive male patients (18 eyes) undergoing vitrectomy for Eales' disease were studied prospectively. Intraoperative diagnosis was vitreous hemorrhage (VH) in nine cases, traction retinal detachment (TRD) in four, VH and TRD in three, and combined traction-rhegmatogenous retinal detachment in two. Epiretinal membranes (ERMs) obtained during surgery were studied using light microscopy and immunohistochemistry. RESULTS: An incomplete posterior vitreous detachment was observed in all eyes. Multifocal vitreoretinal adhesions were evident in 83.3% of eyes. The proliferation was fibrovascular in 10 eyes and fibrous in eight. A radial traction fold extending from optic disk to periphery was observed in three eyes. A double-layered membrane, probably the result of vitreoschisis, caused tangential traction. ERMs consisted principally of type II collagen and the cellular element was predominantly composed of lymphocytes, glial cells, and macrophage-like cells (probably hyalocytes). CONCLUSIONS: Fibrous and fibrovascular proliferations have multiple areas of adhesions to the posterior vitreous cortex. The presence of type II collagen in the ERM indicates a possible vitreous collagen component to the double-layered membranes (vitreoschisis). Recognition of the double-layered membranes aids in relief of traction during surgery by delamination.

Adult↗
PubMed1999

pH-adjusted periocular anaesthesia for primary vitreoretinal surgery.

PURPOSE: To evaluate the efficacy of pH-adjusted bupivacaine in conjunction with medial orbital periconal block (periocular anaesthesia). METHODS: Sixty consecutive patients undergoing primary vitreoretinal surgery were enrolled prospectively. RESULTS: Adequate anaesthesia and akinesia with no intraoperative supplementation was achieved in 53 eyes (88.3%). Factors influencing intraoperative supplementation were combined vitrectomy with scleral buckling (p = 0.005) and duration of surgery of more than 2 hours (p = 0.001). No ocular or systemic complication resulted. CONCLUSION: pH-adjusted periocular anaesthesia is safe and effective in patients undergoing primary vitreoretinal surgery.

Adult↗
PubMed1999

Bisected macula following retrobulbar steroid injection.

A case of bilateral accidental globe penetration during administration of retrobulbar steroid for bilateral optic neuritis is discussed. One eye with bisected macula was managed successfully by vitrectomy, internal gas tamponade, and postoperative laser to the edges of the retinal tear. The fellow eye was blind due to central retinal artery occlusion.

Adult↗
PubMed1998

Long term visual results of vitrectomy for Eales disease complications.

BACKGROUND AND OBJECTIVES: Complications of Eales disease can cause visual loss. Long term visual prognosis following vitrectomy for Eales disease complications has been studied. PATIENTS AND METHODS: Retrospective analysis of 64 eyes of 57 patients who underwent vitrectomy for Eales disease complications with a minimum follow-up of 60 months. RESULTS: 62.4% eyes at 2 months and 71.8% at 60 months had 6/60 or better visual acuity. Visual acuities for individual cases were quite stable at the 60 month follow up with 50 eyes (78.5%) either maintaining or improving upon their 2 month post operative visual acuity. CONCLUSION: Visual acuity improves after vitrectomy in majority of patients with Eales disease complications and remains stable on long term follow-up.

Adolescent↗
PubMed1998

Subretinal fibrosis and nonrhegmatogenous retinal detachment associated with multifocal central serous chorioretinopathy.

PURPOSE: To report the rare occurrence of subretinal fibrosis in patients with multifocal central serous chorioretinopathy and evaluate the role of systemic corticosteroids and the effects of laser photocoagulation on multifocal leaks. METHODS: A total of 29 patients (mean age, 37.7 years; 89.7% male) treated for subretinal fibrosis and multifocal central serous chorioretinopathy from 1983-1995 were reviewed retrospectively. Mean follow up was 26 months (range, 6.8-81 months). RESULTS: Retinal detachment involved the macula in 72.4% cases. Fluorescein angiography showed a mean of 6.7 (range, 2-22) central serous chorioretinopathy leaks and a mean of 1.8 (range, 1-5) retinal pigment epithelial detachments. The fundus pictures of 23 patients who were taking systemic corticosteroids showed no improvement. Following laser treatment, however, retinal reattachment was obtained in all eyes, and improvement in visual acuity of > 2 Snellen lines was noted in 68.9% of patients. CONCLUSIONS: The presence of subretinal fibrosis with secondary retinal detachment in otherwise healthy young patients, particularly in men, should alert the physician to look for multifocal central serous retinopathy leaks. Systemic corticosteroids did not prove effective in treating these patients, although laser treatment is recommended for each leak identified on an angiogram.

Adult↗
PubMed1997

A multivariate analysis of anatomic success of recurrent retinal detachment treated with pneumatic retinopexy.

PURPOSE: The purpose of the study is to determine the success rate of pneumatic retinopexy (PR) after failed scleral buckling and to elucidate the predictors for anatomic failure by multiple logistic regression analysis. METHODS: Thirty-six eyes with recurrent retinal detachment after failed scleral buckling underwent PR. Intraocular tamponade was attained with SF6 (20 eyes), C3F8 (13 eyes), and air (3 eyes). Median follow-up was 14 months. RESULTS: Retinal reattachment was obtained in 69.4%. Multivariate analysis identified two risk factors for failure: location of retinal break either on the posterior slope or posterior to buckle (P = 0.01) and extent of retinal detachment greater than two quadrants (P = 0.02). CONCLUSIONS: Pneumatic retinopexy is an effective alternative to revision surgical operations if the leaking retinal break is located on the buckle.

Adolescent↗
PubMed1997

Parabulbar anesthesia for primary vitreoretinal surgery.

PURPOSE: The efficacy and safety of parabulbar anesthesia was investigated prospectively in 100 patients undergoing primary vitreoretinal surgery. METHODS: The technique involved three steps: (1) orbicularis oculi injection, (2) subconjunctival injection, and (3) sub-Tenon irrigation. The effect of anesthesia was graded 0 to 5 depending on inadequate anesthesia-akinesia with or without local supplementation. Ninety-three patients underwent vitrectomy without buckling and 4 with an encircling band; 3 had scleral buckling. Mean duration of surgery was 89.38 minutes. RESULTS: In 69% of patients (grades 4 and 5), no supplementation was required and in 31% (grades 1-3), local supplementation was needed for inadequate anesthesia or akinesia or both. No ocular or systemic complication occurred. Early onset of anesthesia correlated with adequate anesthesia throughout the procedure (P < 0.04). CONCLUSIONS: Parabulbar anesthesia is a safe and effective technique of local anesthesia in patients undergoing primary vitreoretinal surgery.

Adult↗